This file is indexed.

/usr/share/debian-reference/ch09.en.html is in debian-reference-en 2.68.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
6498
6499
6500
6501
6502
6503
6504
6505
6506
6507
6508
6509
6510
6511
6512
6513
6514
6515
6516
6517
6518
6519
6520
6521
6522
6523
6524
6525
6526
6527
6528
6529
6530
6531
6532
6533
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
6544
6545
6546
6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
6616
6617
6618
6619
6620
6621
6622
6623
6624
6625
6626
6627
6628
6629
6630
6631
6632
6633
6634
6635
6636
6637
6638
6639
6640
6641
6642
6643
6644
6645
6646
6647
6648
6649
6650
6651
6652
6653
6654
6655
6656
6657
6658
6659
6660
6661
6662
6663
6664
6665
6666
6667
6668
6669
6670
6671
6672
6673
6674
6675
6676
6677
6678
6679
6680
6681
6682
6683
6684
6685
6686
6687
6688
6689
6690
6691
6692
6693
6694
6695
6696
6697
6698
6699
6700
6701
6702
6703
6704
6705
6706
6707
6708
6709
6710
6711
6712
6713
6714
6715
6716
6717
6718
6719
6720
6721
6722
6723
6724
6725
6726
6727
6728
6729
6730
6731
6732
6733
6734
6735
6736
6737
6738
6739
6740
6741
6742
6743
6744
6745
6746
6747
6748
6749
6750
6751
6752
6753
6754
6755
6756
6757
6758
6759
6760
6761
6762
6763
6764
6765
6766
6767
6768
6769
6770
6771
6772
6773
6774
6775
6776
6777
6778
6779
6780
6781
6782
6783
6784
6785
6786
6787
6788
6789
6790
6791
6792
6793
6794
6795
6796
6797
6798
6799
6800
6801
6802
6803
6804
6805
6806
6807
6808
6809
6810
6811
6812
6813
6814
6815
6816
6817
6818
6819
6820
6821
6822
6823
6824
6825
6826
6827
6828
6829
6830
6831
6832
6833
6834
6835
6836
6837
6838
6839
6840
6841
6842
6843
6844
6845
6846
6847
6848
6849
6850
6851
6852
6853
6854
6855
6856
6857
6858
6859
6860
6861
6862
6863
6864
6865
6866
6867
6868
6869
6870
6871
6872
6873
6874
6875
6876
6877
6878
6879
6880
6881
6882
6883
6884
6885
6886
6887
6888
6889
6890
6891
6892
6893
6894
6895
6896
6897
6898
6899
6900
6901
6902
6903
6904
6905
6906
6907
6908
6909
6910
6911
6912
6913
6914
6915
6916
6917
6918
6919
6920
6921
6922
6923
6924
6925
6926
6927
6928
6929
6930
6931
6932
6933
6934
6935
6936
6937
6938
6939
6940
6941
6942
6943
6944
6945
6946
6947
6948
6949
6950
6951
6952
6953
6954
6955
6956
6957
6958
6959
6960
6961
6962
6963
6964
6965
6966
6967
6968
6969
6970
6971
6972
6973
6974
6975
6976
6977
6978
6979
6980
6981
6982
6983
6984
6985
6986
6987
6988
6989
6990
6991
6992
6993
6994
6995
6996
6997
6998
6999
7000
7001
7002
7003
7004
7005
7006
7007
7008
7009
7010
7011
7012
7013
7014
7015
7016
7017
7018
7019
7020
7021
7022
7023
7024
7025
7026
7027
7028
7029
7030
7031
7032
7033
7034
7035
7036
7037
7038
7039
7040
7041
7042
7043
7044
7045
7046
7047
7048
7049
7050
7051
7052
7053
7054
7055
7056
7057
7058
7059
7060
7061
7062
7063
7064
7065
7066
7067
7068
7069
7070
7071
7072
7073
7074
7075
7076
7077
7078
7079
7080
7081
7082
7083
7084
7085
7086
7087
7088
7089
7090
7091
7092
7093
7094
7095
7096
7097
7098
7099
7100
7101
7102
7103
7104
7105
7106
7107
7108
7109
7110
7111
7112
7113
7114
7115
7116
7117
7118
7119
7120
7121
7122
7123
7124
7125
7126
7127
7128
7129
7130
7131
7132
7133
7134
7135
7136
7137
7138
7139
7140
7141
7142
7143
7144
7145
7146
7147
7148
7149
7150
7151
7152
7153
7154
7155
7156
7157
7158
7159
7160
7161
7162
7163
7164
7165
7166
7167
7168
7169
7170
7171
7172
7173
7174
7175
7176
7177
7178
7179
7180
7181
7182
7183
7184
7185
7186
7187
7188
7189
7190
7191
7192
7193
7194
7195
7196
7197
7198
7199
7200
7201
7202
7203
7204
7205
7206
7207
7208
7209
7210
7211
7212
7213
7214
7215
7216
7217
7218
7219
7220
7221
7222
7223
7224
7225
7226
7227
7228
7229
7230
7231
7232
7233
7234
7235
7236
7237
7238
7239
7240
7241
7242
7243
7244
7245
7246
7247
7248
7249
7250
7251
7252
7253
7254
7255
7256
7257
7258
7259
7260
7261
7262
7263
7264
7265
7266
7267
7268
7269
7270
7271
7272
7273
7274
7275
7276
7277
7278
7279
7280
7281
7282
7283
7284
7285
7286
7287
7288
7289
7290
7291
7292
7293
7294
7295
7296
7297
7298
7299
7300
7301
7302
7303
7304
7305
7306
7307
7308
7309
7310
7311
7312
7313
7314
7315
7316
7317
7318
7319
7320
7321
7322
7323
7324
7325
7326
7327
7328
7329
7330
7331
7332
7333
7334
7335
7336
7337
7338
7339
7340
7341
7342
7343
7344
7345
7346
7347
7348
7349
7350
7351
7352
7353
7354
7355
7356
7357
7358
7359
7360
7361
7362
7363
7364
7365
7366
7367
7368
7369
7370
7371
7372
7373
7374
7375
7376
7377
7378
7379
7380
7381
7382
7383
7384
7385
7386
7387
7388
7389
7390
7391
7392
7393
7394
7395
7396
7397
7398
7399
7400
7401
7402
7403
7404
7405
7406
7407
7408
7409
7410
7411
7412
7413
7414
7415
7416
7417
7418
7419
7420
7421
7422
7423
7424
7425
7426
7427
7428
7429
7430
7431
7432
7433
7434
7435
7436
7437
7438
7439
7440
7441
7442
7443
7444
7445
7446
7447
7448
7449
7450
7451
7452
7453
7454
7455
7456
7457
7458
7459
7460
7461
7462
7463
7464
7465
7466
7467
7468
7469
7470
7471
7472
7473
7474
7475
7476
7477
7478
7479
7480
7481
7482
7483
7484
7485
7486
7487
7488
7489
7490
7491
7492
7493
7494
7495
7496
7497
7498
7499
7500
7501
7502
7503
7504
7505
7506
7507
7508
7509
7510
7511
7512
7513
7514
7515
7516
7517
7518
7519
7520
7521
7522
7523
7524
7525
7526
7527
7528
7529
7530
7531
7532
7533
7534
7535
7536
7537
7538
7539
7540
7541
7542
7543
7544
7545
7546
7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
7572
7573
7574
7575
7576
7577
7578
7579
7580
7581
7582
7583
7584
7585
7586
7587
7588
7589
7590
7591
7592
7593
7594
7595
7596
7597
7598
7599
7600
7601
7602
7603
7604
7605
7606
7607
7608
7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
7626
7627
7628
7629
7630
7631
7632
7633
7634
7635
7636
7637
7638
7639
7640
7641
7642
7643
7644
7645
7646
7647
7648
7649
7650
7651
7652
7653
7654
7655
7656
7657
7658
7659
7660
7661
7662
7663
7664
7665
7666
7667
7668
7669
7670
7671
7672
7673
7674
7675
7676
7677
7678
7679
7680
7681
7682
7683
7684
7685
7686
7687
7688
7689
7690
7691
7692
7693
7694
7695
7696
7697
7698
7699
7700
7701
7702
7703
7704
7705
7706
7707
7708
7709
7710
7711
7712
7713
7714
7715
7716
7717
7718
7719
7720
7721
7722
7723
7724
7725
7726
7727
7728
7729
7730
7731
7732
7733
7734
7735
7736
7737
7738
7739
7740
7741
7742
7743
7744
7745
7746
7747
7748
7749
7750
7751
7752
7753
7754
7755
7756
7757
7758
7759
7760
7761
7762
7763
7764
7765
7766
7767
7768
7769
7770
7771
7772
7773
7774
7775
7776
7777
7778
7779
7780
7781
7782
7783
7784
7785
7786
7787
7788
7789
7790
7791
7792
7793
7794
7795
7796
7797
7798
7799
7800
7801
7802
7803
7804
7805
7806
7807
7808
7809
7810
7811
7812
7813
7814
7815
7816
7817
7818
7819
7820
7821
7822
7823
7824
7825
7826
7827
7828
7829
7830
7831
7832
7833
7834
7835
7836
7837
7838
7839
7840
7841
7842
7843
7844
7845
7846
7847
7848
7849
7850
7851
7852
7853
7854
7855
7856
7857
7858
7859
7860
7861
7862
7863
7864
7865
7866
7867
7868
7869
7870
7871
7872
7873
7874
7875
7876
7877
7878
7879
7880
7881
7882
7883
7884
7885
7886
7887
7888
7889
7890
7891
7892
7893
7894
7895
7896
7897
7898
7899
7900
7901
7902
7903
7904
7905
7906
7907
7908
7909
7910
7911
7912
7913
7914
7915
7916
7917
7918
7919
7920
7921
7922
7923
7924
7925
7926
7927
7928
7929
7930
7931
7932
7933
7934
7935
7936
7937
7938
7939
7940
7941
7942
7943
7944
7945
7946
7947
7948
7949
7950
7951
7952
7953
7954
7955
7956
7957
7958
7959
7960
7961
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <title>Chapter 9. System tips</title>
    <link rel="stylesheet" type="text/css" href="debian-reference.css"/>
    <meta name="generator" content="DocBook XSL Stylesheets V1.79.1"/>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
    <link rel="home" href="index.en.html" title="Debian Reference"/>
    <link rel="up" href="index.en.html" title="Debian Reference"/>
    <link rel="prev" href="ch08.en.html" title="Chapter 8. I18N and L10N"/>
    <link rel="next" href="ch10.en.html" title="Chapter 10. Data management"/>
  </head>
  <body>
    <div class="navheader">
      <table width="100%" summary="Navigation header">
        <tr>
          <th colspan="3" align="center">Chapter 9. System tips</th>
        </tr>
        <tr>
          <td align="left"><a accesskey="p" href="ch08.en.html"><img src="images/prev.png" alt="Prev"/></a> </td>
          <th width="60%" align="center"> </th>
          <td align="right"> <a accesskey="n" href="ch10.en.html"><img src="images/next.png" alt="Next"/></a></td>
        </tr>
      </table>
      <hr/>
    </div>
    <div class="chapter">
      <div class="titlepage">
        <div>
          <div>
            <h1 class="title"><a id="_system_tips"/>Chapter 9. System tips</h1>
          </div>
        </div>
      </div>
      <div class="toc">
        <p>
          <strong>Table of Contents</strong>
        </p>
        <dl class="toc">
          <dt>
            <span class="section">
              <a href="ch09.en.html#_the_screen_program">9.1. The screen program</a>
            </span>
          </dt>
          <dd>
            <dl>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_the_use_scenario_for_screen_1">9.1.1. The use scenario for screen(1)</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_key_bindings_for_the_screen_command">9.1.2. Key bindings for the screen command</a>
                </span>
              </dt>
            </dl>
          </dd>
          <dt>
            <span class="section">
              <a href="ch09.en.html#_data_recording_and_presentation">9.2. Data recording and presentation</a>
            </span>
          </dt>
          <dd>
            <dl>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_the_log_daemon">9.2.1. The log daemon</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_log_analyzer">9.2.2. Log analyzer</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_recording_the_shell_activities_cleanly">9.2.3. Recording the shell activities cleanly</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_customized_display_of_text_data">9.2.4. Customized display of text data</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_customized_display_of_time_and_date">9.2.5. Customized display of time and date</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_colorized_shell_echo">9.2.6. Colorized shell echo</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_colorized_commands">9.2.7. Colorized commands</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_recording_the_editor_activities_for_complex_repeats">9.2.8. Recording the editor activities for complex repeats</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_recording_the_graphic_image_of_an_x_application">9.2.9. Recording the graphic image of an X application</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_recording_changes_in_configuration_files">9.2.10. Recording changes in configuration files</a>
                </span>
              </dt>
            </dl>
          </dd>
          <dt>
            <span class="section">
              <a href="ch09.en.html#_monitoring_controlling_and_starting_program_activities">9.3. Monitoring, controlling, and starting program activities</a>
            </span>
          </dt>
          <dd>
            <dl>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_timing_a_process">9.3.1. Timing a process</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_the_scheduling_priority">9.3.2. The scheduling priority</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_the_ps_command">9.3.3. The ps command</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_the_top_command">9.3.4. The top command</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_listing_files_opened_by_a_process">9.3.5. Listing files opened by a process</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_tracing_program_activities">9.3.6. Tracing program activities</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_identification_of_processes_using_files_or_sockets">9.3.7. Identification of processes using files or sockets</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_repeating_a_command_with_a_constant_interval">9.3.8. Repeating a command with a constant interval</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_repeating_a_command_looping_over_files">9.3.9. Repeating a command looping over files</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_starting_a_program_from_gui">9.3.10. Starting a program from GUI</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_customizing_program_to_be_started">9.3.11. Customizing program to be started</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_killing_a_process">9.3.12. Killing a process</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_scheduling_tasks_once">9.3.13. Scheduling tasks once</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_scheduling_tasks_regularly">9.3.14. Scheduling tasks regularly</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_alt_sysrq_key">9.3.15. Alt-SysRq key</a>
                </span>
              </dt>
            </dl>
          </dd>
          <dt>
            <span class="section">
              <a href="ch09.en.html#_system_maintenance_tips">9.4. System maintenance tips</a>
            </span>
          </dt>
          <dd>
            <dl>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_who_is_on_the_system">9.4.1. Who is on the system?</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_warning_everyone">9.4.2. Warning everyone</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_hardware_identification">9.4.3. Hardware identification</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_hardware_configuration">9.4.4. Hardware configuration</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_system_and_hardware_time">9.4.5. System and hardware time</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_the_terminal_configuration">9.4.6. The terminal configuration</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_the_sound_infrastructure">9.4.7. The sound infrastructure</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_disabling_the_screen_saver">9.4.8. Disabling the screen saver</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_disabling_beep_sounds">9.4.9. Disabling beep sounds</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_memory_usage">9.4.10. Memory usage</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_system_security_and_integrity_check">9.4.11. System security and integrity check</a>
                </span>
              </dt>
            </dl>
          </dd>
          <dt>
            <span class="section">
              <a href="ch09.en.html#_data_storage_tips">9.5. Data storage tips</a>
            </span>
          </dt>
          <dd>
            <dl>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_disk_space_usage">9.5.1. Disk space usage</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_disk_partition_configuration">9.5.2. Disk partition configuration</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_accessing_partition_using_uuid">9.5.3. Accessing partition using UUID</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_lvm2">9.5.4. LVM2</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_filesystem_configuration">9.5.5. Filesystem configuration</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_filesystem_creation_and_integrity_check">9.5.6. Filesystem creation and integrity check</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_optimization_of_filesystem_by_mount_options">9.5.7. Optimization of filesystem by mount options</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_optimization_of_filesystem_via_superblock">9.5.8. Optimization of filesystem via superblock</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_optimization_of_hard_disk">9.5.9. Optimization of hard disk</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_optimization_of_solid_state_drive">9.5.10. Optimization of solid state drive</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_using_smart_to_predict_hard_disk_failure">9.5.11. Using SMART to predict hard disk failure</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_specify_temporary_storage_directory_via_tmpdir">9.5.12. Specify temporary storage directory via $TMPDIR</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_expansion_of_usable_storage_space_via_lvm">9.5.13. Expansion of usable storage space via LVM</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_expansion_of_usable_storage_space_by_mounting_another_partition">9.5.14. Expansion of usable storage space by mounting another partition</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_expansion_of_usable_storage_space_by_bind_mounting_another_directory">9.5.15. Expansion of usable storage space by bind-mounting another directory</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_expansion_of_usable_storage_space_using_symlink">9.5.16. Expansion of usable storage space using symlink</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_expansion_of_usable_storage_space_using_overlayfs">9.5.17. Expansion of usable storage space using overlayfs</a>
                </span>
              </dt>
            </dl>
          </dd>
          <dt>
            <span class="section">
              <a href="ch09.en.html#_the_disk_image">9.6. The disk image</a>
            </span>
          </dt>
          <dd>
            <dl>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_making_the_disk_image_file">9.6.1. Making the disk image file</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_writing_directly_to_the_disk">9.6.2. Writing directly to the disk</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_mounting_the_disk_image_file">9.6.3. Mounting the disk image file</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_cleaning_a_disk_image_file">9.6.4. Cleaning a disk image file</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_making_the_empty_disk_image_file">9.6.5. Making the empty disk image file</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_making_the_iso9660_image_file">9.6.6. Making the ISO9660 image file</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_writing_directly_to_the_cd_dvd_r_rw">9.6.7. Writing directly to the CD/DVD-R/RW</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_mounting_the_iso9660_image_file">9.6.8. Mounting the ISO9660 image file</a>
                </span>
              </dt>
            </dl>
          </dd>
          <dt>
            <span class="section">
              <a href="ch09.en.html#_the_binary_data">9.7. The binary data</a>
            </span>
          </dt>
          <dd>
            <dl>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_viewing_and_editing_binary_data">9.7.1. Viewing and editing binary data</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_manipulating_files_without_mounting_disk">9.7.2. Manipulating files without mounting disk</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_data_redundancy">9.7.3. Data redundancy</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_data_file_recovery_and_forensic_analysis">9.7.4. Data file recovery and forensic analysis</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_splitting_a_large_file_into_small_files">9.7.5. Splitting a large file into small files</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_clearing_file_contents">9.7.6. Clearing file contents</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_dummy_files">9.7.7. Dummy files</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_erasing_an_entire_hard_disk">9.7.8. Erasing an entire hard disk</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_erasing_unused_area_of_an_hard_disk">9.7.9. Erasing unused area of an hard disk</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_undeleting_deleted_but_still_open_files">9.7.10. Undeleting deleted but still open files</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_searching_all_hardlinks">9.7.11. Searching all hardlinks</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_invisible_disk_space_consumption">9.7.12. Invisible disk space consumption</a>
                </span>
              </dt>
            </dl>
          </dd>
          <dt>
            <span class="section">
              <a href="ch09.en.html#_data_encryption_tips">9.8. Data encryption tips</a>
            </span>
          </dt>
          <dd>
            <dl>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_removable_disk_encryption_with_dm_crypt_luks">9.8.1. Removable disk encryption with dm-crypt/LUKS</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_encrypted_swap_partition_with_dm_crypt">9.8.2. Encrypted swap partition with dm-crypt</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_mounting_encrypted_disk_with_dm_crypt_luks">9.8.3. Mounting encrypted disk with dm-crypt/LUKS</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_automatically_encrypting_files_with_ecryptfs">9.8.4. Automatically encrypting files with eCryptfs</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_automatically_mounting_ecryptfs">9.8.5. Automatically mounting eCryptfs</a>
                </span>
              </dt>
            </dl>
          </dd>
          <dt>
            <span class="section">
              <a href="ch09.en.html#_the_kernel">9.9. The kernel</a>
            </span>
          </dt>
          <dd>
            <dl>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_linux_kernel_2_6_3_x">9.9.1. Linux kernel 2.6/3.x</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_kernel_parameters">9.9.2. Kernel parameters</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_kernel_headers">9.9.3. Kernel headers</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_compiling_the_kernel_and_related_modules">9.9.4. Compiling the kernel and related modules</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_compiling_the_kernel_source_debian_kernel_team_recommendation">9.9.5. Compiling the kernel source: Debian Kernel Team recommendation</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_hardware_drivers_and_firmware">9.9.6. Hardware drivers and firmware</a>
                </span>
              </dt>
            </dl>
          </dd>
          <dt>
            <span class="section">
              <a href="ch09.en.html#_virtualized_system">9.10. Virtualized system</a>
            </span>
          </dt>
          <dd>
            <dl>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_virtualization_tools">9.10.1. Virtualization tools</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_virtualization_work_flow">9.10.2. Virtualization work flow</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_mounting_the_virtual_disk_image_file">9.10.3. Mounting the virtual disk image file</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_chroot_system">9.10.4. Chroot system</a>
                </span>
              </dt>
              <dt>
                <span class="section">
                  <a href="ch09.en.html#_multiple_desktop_systems">9.10.5. Multiple desktop systems</a>
                </span>
              </dt>
            </dl>
          </dd>
        </dl>
      </div>
      <p>Here, I describe basic tips to configure and manage systems, mostly from the console.</p>
      <div class="section">
        <div class="titlepage">
          <div>
            <div>
              <h2 class="title"><a id="_the_screen_program"/>9.1. The screen program</h2>
            </div>
          </div>
        </div>
        <p><span class="citerefentry"><span class="refentrytitle">screen</span>(1)</span> is a very useful tool for people to access remote sites via unreliable or intermittent connections since it supports interrupted network connections.</p>
        <div class="table">
          <a id="listofprogramstotworkconnections"/>
          <p class="title">
            <strong>Table 9.1. List of programs to support interrupted network connections</strong>
          </p>
          <div class="table-contents">
            <table class="table" summary="List of programs to support interrupted network connections" border="1">
              <colgroup>
                <col style="text-align: left"/>
                <col style="text-align: left"/>
                <col style="text-align: left"/>
                <col style="text-align: left"/>
              </colgroup>
              <thead>
                <tr>
                  <th style="text-align: left">
    package
    </th>
                  <th style="text-align: left">
    popcon
    </th>
                  <th style="text-align: left">
    size
    </th>
                  <th style="text-align: left">
    description
    </th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/screen">
                <code class="literal">screen</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=screen">V:182, I:289</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/s/screen.html">981</a>
                  </td>
                  <td style="text-align: left">
    terminal multiplexer with VT100/ANSI terminal emulation
    </td>
                </tr>
              </tbody>
            </table>
          </div>
        </div>
        <br class="table-break"/>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_the_use_scenario_for_screen_1"/>9.1.1. The use scenario for screen(1)</h3>
              </div>
            </div>
          </div>
          <p><span class="citerefentry"><span class="refentrytitle">screen</span>(1)</span> not only allows one terminal window to work with multiple processes, but also allows <span class="strong"><strong>remote shell process to survive interrupted connections</strong></span>.  Here is a typical use scenario of <span class="citerefentry"><span class="refentrytitle">screen</span>(1)</span>.</p>
          <div class="orderedlist">
            <ol class="orderedlist">
              <li class="listitem">
                <p>
You login to a remote machine.
</p>
              </li>
              <li class="listitem">
                <p>
You start <code class="literal">screen</code> on a single console.
</p>
              </li>
              <li class="listitem">
                <p>
You execute multiple programs in <code class="literal">screen</code> windows created with <code class="literal">^A c</code> ("Control-A" followed by "c").
</p>
              </li>
              <li class="listitem">
                <p>
You switch among the multiple <code class="literal">screen</code> windows by <code class="literal">^A n</code> ("Control-A" followed by "n").
</p>
              </li>
              <li class="listitem">
                <p>
Suddenly you need to leave your terminal, but you don't want to lose your active work by keeping the connection.
</p>
              </li>
              <li class="listitem">
                <p>
You may <span class="strong"><strong>detach</strong></span> the <code class="literal">screen</code> session by any methods.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
Brutally unplug your network connection
</p>
                    </li>
                    <li class="listitem">
                      <p>
Type <code class="literal">^A d</code> ("Control-A" followed by "d") and manually logging out from the remote connection
</p>
                    </li>
                    <li class="listitem">
                      <p>
Type <code class="literal">^A DD</code> ("Control-A" followed by "DD") to have <code class="literal">screen</code> detach and log you out
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
You log in again to the same remote machine (even from a different terminal).
</p>
              </li>
              <li class="listitem">
                <p>
You start <code class="literal">screen</code> as "<code class="literal">screen -r</code>".
</p>
              </li>
              <li class="listitem">
                <p><code class="literal">screen</code> magically <span class="strong"><strong>reattaches</strong></span> all previous <code class="literal">screen</code> windows with all actively running programs.
</p>
              </li>
            </ol>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You can save connection fees with <code class="literal">screen</code> for metered network connections such as dial-up and packet ones, because you can leave a process active while disconnected, and then re-attach it later when you connect again.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_key_bindings_for_the_screen_command"/>9.1.2. Key bindings for the screen command</h3>
              </div>
            </div>
          </div>
          <p>In a <code class="literal">screen</code> session, all keyboard inputs are sent to your current window except for the command keystroke.  All <code class="literal">screen</code> command keystrokes are entered by typing <code class="literal">^A</code> ("Control-A") plus a single key [plus any parameters].  Here are important ones to remember.</p>
          <div class="table">
            <a id="listofkeybindingsforscreen"/>
            <p class="title">
              <strong>Table 9.2. List of key bindings for screen</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of key bindings for screen" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    key binding
    </th>
                    <th style="text-align: left">
    meaning
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A ?</code>
                </td>
                    <td style="text-align: left">
    show a help screen (display key bindings)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A c</code>
                </td>
                    <td style="text-align: left">
    create a new window and switch to it
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A n</code>
                </td>
                    <td style="text-align: left">
    go to next window
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A p</code>
                </td>
                    <td style="text-align: left">
    go to previous window
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A 0</code>
                </td>
                    <td style="text-align: left">
    go to window number 0
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A 1</code>
                </td>
                    <td style="text-align: left">
    go to window number 1
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A w</code>
                </td>
                    <td style="text-align: left">
    show a list of windows
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A a</code>
                </td>
                    <td style="text-align: left">
    send a Ctrl-A to current window as keyboard input
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A h</code>
                </td>
                    <td style="text-align: left">
    write a hardcopy of current window to file
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A H</code>
                </td>
                    <td style="text-align: left">
    begin/end logging current window to file
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A ^X</code>
                </td>
                    <td style="text-align: left">
    lock the terminal (password protected)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A d</code>
                </td>
                    <td style="text-align: left">
    detach screen session from the terminal
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">^A DD</code>
                </td>
                    <td style="text-align: left">
    detach screen session and log out
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <p>See <span class="citerefentry"><span class="refentrytitle">screen</span>(1)</span> for details.</p>
        </div>
      </div>
      <div class="section">
        <div class="titlepage">
          <div>
            <div>
              <h2 class="title"><a id="_data_recording_and_presentation"/>9.2. Data recording and presentation</h2>
            </div>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_the_log_daemon"/>9.2.1. The log daemon</h3>
              </div>
            </div>
          </div>
          <p>Many programs record their activities under the "<code class="literal">/var/log/</code>" directory.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
The kernel log daemon: <span class="citerefentry"><span class="refentrytitle">klogd</span>(8)</span>
</p>
              </li>
              <li class="listitem">
                <p>
The system log daemon: <span class="citerefentry"><span class="refentrytitle">rsyslogd</span>(8)</span>
</p>
              </li>
            </ul>
          </div>
          <p>See <a class="xref" href="ch03.en.html#_the_system_message" title="3.2.9. The system message">Section 3.2.9, “The system message”</a> and <a class="xref" href="ch03.en.html#_the_kernel_message" title="3.2.10. The kernel message">Section 3.2.10, “The kernel message”</a>.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_log_analyzer"/>9.2.2. Log analyzer</h3>
              </div>
            </div>
          </div>
          <p>Here are notable log analyzers ("<code class="literal">~Gsecurity::log-analyzer</code>" in <span class="citerefentry"><span class="refentrytitle">aptitude</span>(8)</span>).</p>
          <div class="table">
            <a id="listofsystemloganalyzers"/>
            <p class="title">
              <strong>Table 9.3. List of system log analyzers</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of system log analyzers" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/logwatch">
                  <code class="literal">logwatch</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=logwatch">V:19, I:21</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/l/logwatch.html">2214</a>
                    </td>
                    <td style="text-align: left">
    log analyzer with nice output written in Perl
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/fail2ban">
                  <code class="literal">fail2ban</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=fail2ban">V:96, I:108</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/f/fail2ban.html">1290</a>
                    </td>
                    <td style="text-align: left">
    ban IPs that cause multiple authentication errors
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/analog">
                  <code class="literal">analog</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=analog">V:5, I:127</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/a/analog.html">3529</a>
                    </td>
                    <td style="text-align: left">
    web server log analyzer
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/awstats">
                  <code class="literal">awstats</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=awstats">V:12, I:20</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/a/awstats.html">6799</a>
                    </td>
                    <td style="text-align: left">
    powerful and featureful web server log analyzer
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/sarg">
                  <code class="literal">sarg</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=sarg">V:6, I:6</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/sarg.html">432</a>
                    </td>
                    <td style="text-align: left">
    squid analysis report generator
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/pflogsumm">
                  <code class="literal">pflogsumm</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=pflogsumm">V:1, I:4</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/p/pflogsumm.html">111</a>
                    </td>
                    <td style="text-align: left">
    Postfix log entry summarizer
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/syslog-summary">
                  <code class="literal">syslog-summary</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=syslog-summary">V:1, I:4</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/syslog-summary.html">30</a>
                    </td>
                    <td style="text-align: left">
    summarize the contents of a syslog log file
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/fwlogwatch">
                  <code class="literal">fwlogwatch</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=fwlogwatch">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/f/fwlogwatch.html">474</a>
                    </td>
                    <td style="text-align: left">
    firewall log analyzer
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/squidview">
                  <code class="literal">squidview</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=squidview">V:0, I:2</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/squidview.html">192</a>
                    </td>
                    <td style="text-align: left">
    monitor and analyze squid access.log files
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/swatch">
                  <code class="literal">swatch</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=swatch">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/swatch.html">112</a>
                    </td>
                    <td style="text-align: left">
    log file viewer with regexp matching, highlighting, and hooks
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/crm114">
                  <code class="literal">crm114</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=crm114">V:0, I:1</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/c/crm114.html">1099</a>
                    </td>
                    <td style="text-align: left">
    Controllable Regex Mutilator and Spam Filter (CRM114)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/icmpinfo">
                  <code class="literal">icmpinfo</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=icmpinfo">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/i/icmpinfo.html">39</a>
                    </td>
                    <td style="text-align: left">
    interpret ICMP messages
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p><a class="ulink" href="http://crm114.sourceforge.net/">CRM114</a> provides language infrastructure to write <span class="strong"><strong>fuzzy</strong></span> filters with the <a class="ulink" href="http://www.laurikari.net/tre/">TRE regex library</a>.  Its popular use is spam mail filter but it can be used as log analyzer.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_recording_the_shell_activities_cleanly"/>9.2.3. Recording the shell activities cleanly</h3>
              </div>
            </div>
          </div>
          <p>The simple use of <span class="citerefentry"><span class="refentrytitle">script</span>(1)</span> (see <a class="xref" href="ch01.en.html#_recording_the_shell_activities" title="1.4.9. Recording the shell activities">Section 1.4.9, “Recording the shell activities”</a>) to record shell activity produces a file with control characters.  This can be avoided by using <span class="citerefentry"><span class="refentrytitle">col</span>(1)</span> as the following.</p>
          <pre class="screen">$ script
Script started, file is typescript</pre>
          <p>Do whatever … and press <code class="literal">Ctrl-D</code> to exit <code class="literal">script</code>.</p>
          <pre class="screen">$ col -bx &lt;typescript &gt;cleanedfile
$ vim cleanedfile</pre>
          <p>If you don't have <code class="literal">script</code> (for example, during the boot process in the initramfs), you can use the following instead.</p>
          <pre class="screen">$ sh -i 2&gt;&amp;1 | tee typescript</pre>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Some <code class="literal">x-terminal-emulator</code> such as <code class="literal">gnome-terminal</code> can record.  You may wish to extend line buffer for scrollback.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You may use <span class="citerefentry"><span class="refentrytitle">screen</span>(1)</span> with "<code class="literal">^A H</code>" (see <a class="xref" href="ch09.en.html#_key_bindings_for_the_screen_command" title="9.1.2. Key bindings for the screen command">Section 9.1.2, “Key bindings for the screen command”</a>) to perform recording of console.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You may use <span class="citerefentry"><span class="refentrytitle">emacs</span>(1)</span> with "<code class="literal">M-x shell</code>", "<code class="literal">M-x eshell</code>", or "<code class="literal">M-x term</code>" to perform recording of console.  You may later use "<code class="literal">C-x C-w</code>" to write the buffer to a file.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_customized_display_of_text_data"/>9.2.4. Customized display of text data</h3>
              </div>
            </div>
          </div>
          <p>Although pager tools such as <span class="citerefentry"><span class="refentrytitle">more</span>(1)</span> and <span class="citerefentry"><span class="refentrytitle">less</span>(1)</span> (see <a class="xref" href="ch01.en.html#_the_pager" title="1.4.5. The pager">Section 1.4.5, “The pager”</a>) and custom tools for highlighting and formatting (see <a class="xref" href="ch11.en.html#_highlighting_and_formatting_plain_text_data" title="11.1.8. Highlighting and formatting plain text data">Section 11.1.8, “Highlighting and formatting plain text data”</a>) can display text data nicely, general purpose editors (see <a class="xref" href="ch01.en.html#_the_text_editor" title="1.4.6. The text editor">Section 1.4.6, “The text editor”</a>) are most versatile and customizable.</p>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>For <span class="citerefentry"><span class="refentrytitle">vim</span>(1)</span> and its pager mode alias <span class="citerefentry"><span class="refentrytitle">view</span>(1)</span>, "<code class="literal">:set hls</code>" enables highlighted search.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_customized_display_of_time_and_date"/>9.2.5. Customized display of time and date</h3>
              </div>
            </div>
          </div>
          <p>The default display format of time and date by the "<code class="literal">ls -l</code>" command depends on the <span class="strong"><strong>locale</strong></span> (see <a class="xref" href="ch01.en.html#_timestamps" title="1.2.6. Timestamps">Section 1.2.6, “Timestamps”</a> for value).  The "<code class="literal">$LANG</code>" variable is referred first and it can be overridden by the "<code class="literal">$LC_TIME</code>" variable.</p>
          <p>The actual default display format for each locale depends on the version of  the standard C library (the <code class="literal">libc6</code> package) used.  I.e., different releases of Debian had different defaults.</p>
          <p>If you really wish to customize this display format of time and date beyond the <span class="strong"><strong>locale</strong></span>, you should set the <span class="strong"><strong>time style value</strong></span> by the "<code class="literal">--time-style</code>" argument or by the "<code class="literal">$TIME_STYLE</code>" value (see <span class="citerefentry"><span class="refentrytitle">ls</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">date</span>(1)</span>, "<code class="literal">info coreutils 'ls invocation'</code>").</p>
          <div class="table">
            <a id="displayexamplesocommandforwheezy"/>
            <p class="title">
              <strong>Table 9.4. Display examples of time and date for the "<code class="literal">ls -l</code>" command for <code class="literal">wheezy</code></strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="Display examples of time and date for the &quot;ls -l&quot; command for wheezy" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    time style value
    </th>
                    <th style="text-align: left">
    locale
    </th>
                    <th style="text-align: left">
    display of time and date
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">iso</code>
                </td>
                    <td style="text-align: left">
    any
    </td>
                    <td style="text-align: left">
                  <code class="literal">01-19 00:15</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">long-iso</code>
                </td>
                    <td style="text-align: left">
    any
    </td>
                    <td style="text-align: left">
                  <code class="literal">2009-01-19 00:15</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">full-iso</code>
                </td>
                    <td style="text-align: left">
    any
    </td>
                    <td style="text-align: left">
                  <code class="literal">2009-01-19 00:15:16.000000000 +0900</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">locale</code>
                </td>
                    <td style="text-align: left">
                  <code class="literal">C</code>
                </td>
                    <td style="text-align: left">
                  <code class="literal">Jan 19 00:15</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">locale</code>
                </td>
                    <td style="text-align: left">
                  <code class="literal">en_US.UTF-8</code>
                </td>
                    <td style="text-align: left">
                  <code class="literal">Jan 19 00:15</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">locale</code>
                </td>
                    <td style="text-align: left">
                  <code class="literal">es_ES.UTF-8</code>
                </td>
                    <td style="text-align: left">
                  <code class="literal">ene 19 00:15</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">+%d.%m.%y %H:%M</code>
                </td>
                    <td style="text-align: left">
    any
    </td>
                    <td style="text-align: left">
                  <code class="literal">19.01.09 00:15</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">+%d.%b.%y %H:%M</code>
                </td>
                    <td style="text-align: left"><code class="literal">C</code> or <code class="literal">en_US.UTF-8</code>
    </td>
                    <td style="text-align: left">
                  <code class="literal">19.Jan.09 00:15</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">+%d.%b.%y %H:%M</code>
                </td>
                    <td style="text-align: left">
                  <code class="literal">es_ES.UTF-8</code>
                </td>
                    <td style="text-align: left">
                  <code class="literal">19.ene.09 00:15</code>
                </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You can eliminate typing long option on commandline using command alias, e.g. "<code class="literal">alias ls='ls --time-style=+%d.%m.%y\ %H:%M'</code>" (see <a class="xref" href="ch01.en.html#_command_alias" title="1.5.9. Command alias">Section 1.5.9, “Command alias”</a>).</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p><a class="ulink" href="http://en.wikipedia.org/wiki/ISO_8601">ISO 8601</a> is followed for these iso-formats.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_colorized_shell_echo"/>9.2.6. Colorized shell echo</h3>
              </div>
            </div>
          </div>
          <p>Shell echo to most modern terminals can be colorized using <a class="ulink" href="http://en.wikipedia.org/wiki/ANSI_escape_code">ANSI escape code</a> (see "<code class="literal">/usr/share/doc/xterm/ctlseqs.txt.gz</code>").</p>
          <p>For example, try the following</p>
          <pre class="screen">$ RED=$(printf "\x1b[31m")
$ NORMAL=$(printf "\x1b[0m")
$ REVERSE=$(printf "\x1b[7m")
$ echo "${RED}RED-TEXT${NORMAL} ${REVERSE}REVERSE-TEXT${NORMAL}"</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_colorized_commands"/>9.2.7. Colorized commands</h3>
              </div>
            </div>
          </div>
          <p>Colorized commands are handy for inspecting their output in the interactive environment.  I include the following in my "<code class="literal">~/.bashrc</code>".</p>
          <pre class="screen">if [ "$TERM" != "dumb" ]; then
    eval "`dircolors -b`"
    alias ls='ls --color=always'
    alias ll='ls --color=always -l'
    alias la='ls --color=always -A'
    alias less='less -R'
    alias ls='ls --color=always'
    alias grep='grep --color=always'
    alias egrep='egrep --color=always'
    alias fgrep='fgrep --color=always'
    alias zgrep='zgrep --color=always'
else
    alias ll='ls -l'
    alias la='ls -A'
fi</pre>
          <p>The use of alias limits color effects to the interactive command usage.  It has advantage over exporting environment variable "<code class="literal">export GREP_OPTIONS='--color=auto'</code>" since color can be seen under pager programs such as <span class="citerefentry"><span class="refentrytitle">less</span>(1)</span>.  If you wish to suppress color when piping to other programs, use "<code class="literal">--color=auto</code>" instead in the above example for "<code class="literal">~/.bashrc</code>".</p>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You can turn off these colorizing aliases in the interactive environment by invoking shell with "<code class="literal">TERM=dumb bash</code>".</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_recording_the_editor_activities_for_complex_repeats"/>9.2.8. Recording the editor activities for complex repeats</h3>
              </div>
            </div>
          </div>
          <p>You can record the editor activities for complex repeats.</p>
          <p>For <a class="ulink" href="http://en.wikipedia.org/wiki/Vim_(text_editor)">Vim</a>, as follows.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
"<code class="literal">qa</code>": start recording typed characters into named register "<code class="literal">a</code>".
</p>
              </li>
              <li class="listitem">
                <p>
… editor activities
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">q</code>": end recording typed characters.
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">@a</code>": execute the contents of register "<code class="literal">a</code>".
</p>
              </li>
            </ul>
          </div>
          <p>For <a class="ulink" href="http://en.wikipedia.org/wiki/Emacs">Emacs</a>, as follows.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
"<code class="literal">C-x (</code>": start defining a keyboard macro.
</p>
              </li>
              <li class="listitem">
                <p>
… editor activities
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">C-x )</code>": end defining a keyboard macro.
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">C-x e</code>": execute a keyboard macro.
</p>
              </li>
            </ul>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_recording_the_graphic_image_of_an_x_application"/>9.2.9. Recording the graphic image of an X application</h3>
              </div>
            </div>
          </div>
          <p>There are few ways to record the graphic image of an X application, including an <code class="literal">xterm</code> display.</p>
          <div class="table">
            <a id="listofgraphicimaanipulationtools"/>
            <p class="title">
              <strong>Table 9.5. List of graphic image manipulation tools</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of graphic image manipulation tools" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    command
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/xbase-clients">
                  <code class="literal">xbase-clients</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=xbase-clients">I:68</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/x/xbase-clients.html">46</a>
                    </td>
                    <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">xwd</span>(1)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/gimp">
                  <code class="literal">gimp</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=gimp">V:91, I:507</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/g/gimp.html">16278</a>
                    </td>
                    <td style="text-align: left">
    GUI menu
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/imagemagick">
                  <code class="literal">imagemagick</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=imagemagick">V:142, I:538</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/i/imagemagick.html">192</a>
                    </td>
                    <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">import</span>(1)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/scrot">
                  <code class="literal">scrot</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=scrot">V:8, I:87</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/scrot.html">50</a>
                    </td>
                    <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">scrot</span>(1)</span>
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_recording_changes_in_configuration_files"/>9.2.10. Recording changes in configuration files</h3>
              </div>
            </div>
          </div>
          <p>There are specialized tools to record changes in configuration files with help of DVCS system.</p>
          <div class="table">
            <a id="listofpackagestotionhistoryinvcs"/>
            <p class="title">
              <strong>Table 9.6. List of packages to record configuration history in VCS</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of packages to record configuration history in VCS" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/etckeeper">
                  <code class="literal">etckeeper</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=etckeeper">V:22, I:27</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/e/etckeeper.html">151</a>
                    </td>
                    <td style="text-align: left">
    store configuration files and their metadata with <a class="ulink" href="http://en.wikipedia.org/wiki/Git_(software)">Git</a> (default), <a class="ulink" href="http://en.wikipedia.org/wiki/Mercurial_(software)">Mercurial</a>, or <a class="ulink" href="http://en.wikipedia.org/wiki/Bazaar_(software)">Bazaar</a> (new)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/changetrack">
                  <code class="literal">changetrack</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=changetrack">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/c/changetrack.html">62</a>
                    </td>
                    <td style="text-align: left">
    store configuration files with <a class="ulink" href="http://en.wikipedia.org/wiki/Revision_Control_System">RCS</a> (old)
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <p>I recommend to use the <code class="literal">etckeeper</code> package with <span class="citerefentry"><span class="refentrytitle">git</span>(1)</span> which put entire "<code class="literal">/etc</code>" under VCS control.  Its installation guide and tutorial are found in "<code class="literal">/usr/share/doc/etckeeper/README.gz</code>".</p>
          <p>Essentially, running "<code class="literal">sudo etckeeper init</code>" initializes the git repository for "<code class="literal">/etc</code>" just like the process explained in <a class="xref" href="ch10.en.html#_git_for_recording_configuration_history" title="10.6.5. Git for recording configuration history">Section 10.6.5, “Git for recording configuration history”</a> but with special hook scripts for more thorough setups.</p>
          <p>As you change your configuration, you can use <span class="citerefentry"><span class="refentrytitle">git</span>(1)</span> normally to record them.  It automatically records changes nicely every time you run package management commands, too.</p>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You can browse the change history of "<code class="literal">/etc</code>" by executing "<code class="literal">sudo GIT_DIR=/etc/.git gitk</code>" with clear view for new installed packages, removed packages, and version changes of packages.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
      </div>
      <div class="section">
        <div class="titlepage">
          <div>
            <div>
              <h2 class="title"><a id="_monitoring_controlling_and_starting_program_activities"/>9.3. Monitoring, controlling, and starting program activities</h2>
            </div>
          </div>
        </div>
        <p>Program activities can be monitored and controlled using specialized tools.</p>
        <div class="table">
          <a id="listoftoolsformorogramactivities"/>
          <p class="title">
            <strong>Table 9.7. List of tools for monitoring and controlling program activities</strong>
          </p>
          <div class="table-contents">
            <table class="table" summary="List of tools for monitoring and controlling program activities" border="1">
              <colgroup>
                <col style="text-align: left"/>
                <col style="text-align: left"/>
                <col style="text-align: left"/>
                <col style="text-align: left"/>
              </colgroup>
              <thead>
                <tr>
                  <th style="text-align: left">
    package
    </th>
                  <th style="text-align: left">
    popcon
    </th>
                  <th style="text-align: left">
    size
    </th>
                  <th style="text-align: left">
    description
    </th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/coreutils">
                <code class="literal">coreutils</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=coreutils">V:881, I:999</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/c/coreutils.html">15103</a>
                  </td>
                  <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">nice</span>(1)</span>: run a program with modified scheduling priority
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/bsdutils">
                <code class="literal">bsdutils</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=bsdutils">V:851, I:999</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/b/bsdutils.html">238</a>
                  </td>
                  <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">renice</span>(1)</span>: modify the scheduling priority of a running process
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/procps">
                <code class="literal">procps</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=procps">V:801, I:999</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/p/procps.html">690</a>
                  </td>
                  <td style="text-align: left">
    "<code class="literal">/proc</code>" filesystem utilities: <span class="citerefentry"><span class="refentrytitle">ps</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">top</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">kill</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">watch</span>(1)</span>, …
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/psmisc">
                <code class="literal">psmisc</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=psmisc">V:567, I:970</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/p/psmisc.html">589</a>
                  </td>
                  <td style="text-align: left">
    "<code class="literal">/proc</code>" filesystem utilities: <span class="citerefentry"><span class="refentrytitle">killall</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">fuser</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">peekfd</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">pstree</span>(1)</span>
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/time">
                <code class="literal">time</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=time">V:39, I:819</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/t/time.html">82</a>
                  </td>
                  <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">time</span>(1)</span>: run a program to report system resource usages with respect to time
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/sysstat">
                <code class="literal">sysstat</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=sysstat">V:100, I:119</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/s/sysstat.html">1336</a>
                  </td>
                  <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">sar</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">iostat</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">mpstat</span>(1)</span>, …: system performance tools for Linux
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/isag">
                <code class="literal">isag</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=isag">V:0, I:4</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/i/isag.html">106</a>
                  </td>
                  <td style="text-align: left">
    Interactive System Activity Grapher for sysstat
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/lsof">
                <code class="literal">lsof</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=lsof">V:355, I:945</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/l/lsof.html">440</a>
                  </td>
                  <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">lsof</span>(8)</span>: list files opened by a running process using "<code class="literal">-p</code>" option
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/strace">
                <code class="literal">strace</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=strace">V:21, I:163</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/s/strace.html">1363</a>
                  </td>
                  <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">strace</span>(1)</span>: trace system calls and signals
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/ltrace">
                <code class="literal">ltrace</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=ltrace">V:1, I:22</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/l/ltrace.html">360</a>
                  </td>
                  <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">ltrace</span>(1)</span>: trace library calls
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/xtrace">
                <code class="literal">xtrace</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=xtrace">V:0, I:1</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/x/xtrace.html">333</a>
                  </td>
                  <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">xtrace</span>(1)</span>: trace communication between X11 client and server
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/powertop">
                <code class="literal">powertop</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=powertop">V:6, I:227</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/p/powertop.html">612</a>
                  </td>
                  <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">powertop</span>(1)</span>: information about system power use
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/cron">
                <code class="literal">cron</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=cron">V:877, I:997</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/c/cron.html">251</a>
                  </td>
                  <td style="text-align: left">
    run processes according to a schedule in background from <span class="citerefentry"><span class="refentrytitle">cron</span>(8)</span> daemon
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/anacron">
                <code class="literal">anacron</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=anacron">V:450, I:534</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/a/anacron.html">62</a>
                  </td>
                  <td style="text-align: left">
    cron-like command scheduler for systems that don't run 24 hours a day
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/at">
                <code class="literal">at</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=at">V:482, I:828</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/a/at.html">145</a>
                  </td>
                  <td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">at</span>(1)</span> or <span class="citerefentry"><span class="refentrytitle">batch</span>(1)</span>: run a job at a specified time or below certain load level
    </td>
                </tr>
              </tbody>
            </table>
          </div>
        </div>
        <br class="table-break"/>
        <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
          <table border="0" summary="Tip">
            <tr>
              <td rowspan="2" align="center" valign="top">
                <img alt="[Tip]" src="images/tip.png"/>
              </td>
              <th align="left">Tip</th>
            </tr>
            <tr>
              <td align="left" valign="top">
                <p>The <code class="literal">procps</code> packages provide very basics of monitoring, controlling, and starting program activities.  You should learn all of them.</p>
              </td>
            </tr>
          </table>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_timing_a_process"/>9.3.1. Timing a process</h3>
              </div>
            </div>
          </div>
          <p>Display time used by the process invoked by the command.</p>
          <pre class="screen"># time some_command &gt;/dev/null
real    0m0.035s       # time on wall clock (elapsed real time)
user    0m0.000s       # time in user mode
sys     0m0.020s       # time in kernel mode</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_the_scheduling_priority"/>9.3.2. The scheduling priority</h3>
              </div>
            </div>
          </div>
          <p>A nice value is used to control the scheduling priority for the process.</p>
          <div class="table">
            <a id="listofnicevalueshedulingpriority"/>
            <p class="title">
              <strong>Table 9.8. List of nice values for the scheduling priority</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of nice values for the scheduling priority" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    nice value
    </th>
                    <th style="text-align: left">
    scheduling priority
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
    19
    </td>
                    <td style="text-align: left">
    lowest priority process (nice)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    0
    </td>
                    <td style="text-align: left">
    very high priority process for user
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    -20
    </td>
                    <td style="text-align: left">
    very high priority process for root (not-nice)
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <pre class="screen"># nice  -19 top                                      # very nice
# nice --20 wodim -v -eject speed=2 dev=0,0 disk.img # very fast</pre>
          <p>Sometimes an extreme nice value does more harm than good to the system.  Use this command carefully.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_the_ps_command"/>9.3.3. The ps command</h3>
              </div>
            </div>
          </div>
          <p>The <span class="citerefentry"><span class="refentrytitle">ps</span>(1)</span> command on a Debian system support both BSD and SystemV features and helps to identify the process activity statically.</p>
          <div class="table">
            <a id="listofpscommandstyles"/>
            <p class="title">
              <strong>Table 9.9. List of ps command styles</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of ps command styles" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    style
    </th>
                    <th style="text-align: left">
    typical command
    </th>
                    <th style="text-align: left">
    feature
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
    BSD
    </td>
                    <td style="text-align: left">
                  <code class="literal">ps aux</code>
                </td>
                    <td style="text-align: left">
    display %CPU %MEM
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    System V
    </td>
                    <td style="text-align: left">
                  <code class="literal">ps -efH</code>
                </td>
                    <td style="text-align: left">
    display PPID
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <p>For the zombie (defunct) children process, you can kill them by the parent process ID identified in the "<code class="literal">PPID</code>" field.</p>
          <p>The <span class="citerefentry"><span class="refentrytitle">pstree</span>(1)</span> command display a tree of processes.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_the_top_command"/>9.3.4. The top command</h3>
              </div>
            </div>
          </div>
          <p><span class="citerefentry"><span class="refentrytitle">top</span>(1)</span> on the Debian system has rich features and helps to identify what process is acting funny dynamically.</p>
          <p>Its is an interactive full screen program.  You can get its usage help press by pressing the "h"-key and terminate it by pressing the "q"-key.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_listing_files_opened_by_a_process"/>9.3.5. Listing files opened by a process</h3>
              </div>
            </div>
          </div>
          <p>You can list all files opened by a process with a process ID (PID), e.g. 1, by the following.</p>
          <pre class="screen">$ sudo lsof -p 1</pre>
          <p>PID=1 is usually the <code class="literal">init</code> program.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_tracing_program_activities"/>9.3.6. Tracing program activities</h3>
              </div>
            </div>
          </div>
          <p>You can trace program activity with <span class="citerefentry"><span class="refentrytitle">strace</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">ltrace</span>(1)</span>, or <span class="citerefentry"><span class="refentrytitle">xtrace</span>(1)</span> for system calls and signals, library calls, or communication between X11 client and server.</p>
          <p>You can trace system calls of the <code class="literal">ls</code> command as the following.</p>
          <pre class="screen">$ sudo strace ls</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_identification_of_processes_using_files_or_sockets"/>9.3.7. Identification of processes using files or sockets</h3>
              </div>
            </div>
          </div>
          <p>You can also identify processes using files by <span class="citerefentry"><span class="refentrytitle">fuser</span>(1)</span>, e.g. for "<code class="literal">/var/log/mail.log</code>" by the following.</p>
          <pre class="screen">$ sudo fuser -v /var/log/mail.log
                     USER        PID ACCESS COMMAND
/var/log/mail.log:   root       2946 F.... rsyslogd</pre>
          <p>You see that file "<code class="literal">/var/log/mail.log</code>" is open for writing by the <span class="citerefentry"><span class="refentrytitle">rsyslogd</span>(8)</span> command.</p>
          <p>You can also identify processes using sockets by <span class="citerefentry"><span class="refentrytitle">fuser</span>(1)</span>, e.g. for "<code class="literal">smtp/tcp</code>" by the following.</p>
          <pre class="screen">$ sudo fuser -v smtp/tcp
                     USER        PID ACCESS COMMAND
smtp/tcp:            Debian-exim   3379 F.... exim4</pre>
          <p>Now you know your system runs <span class="citerefentry"><span class="refentrytitle">exim4</span>(8)</span> to handle <a class="ulink" href="http://en.wikipedia.org/wiki/Transmission_Control_Protocol">TCP</a> connections to <a class="ulink" href="http://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol">SMTP</a> port (25).</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_repeating_a_command_with_a_constant_interval"/>9.3.8. Repeating a command with a constant interval</h3>
              </div>
            </div>
          </div>
          <p><span class="citerefentry"><span class="refentrytitle">watch</span>(1)</span> executes a program repeatedly with a constant interval while showing its output in fullscreen.</p>
          <pre class="screen">$ watch w</pre>
          <p>This displays who is logged on to the system updated every 2 seconds.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_repeating_a_command_looping_over_files"/>9.3.9. Repeating a command looping over files</h3>
              </div>
            </div>
          </div>
          <p>There are several ways to repeat a command looping over files matching some condition, e.g. matching glob pattern "<code class="literal">*.ext</code>".</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
Shell for-loop method (see <a class="xref" href="ch12.en.html#_shell_loops" title="12.1.4. Shell loops">Section 12.1.4, “Shell loops”</a>):
</p>
              </li>
            </ul>
          </div>
          <pre class="screen">for x in *.ext; do if [ -f "$x"]; then command "$x" ; fi; done</pre>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">find</span>(1)</span> and <span class="citerefentry"><span class="refentrytitle">xargs</span>(1)</span> combination:
</p>
              </li>
            </ul>
          </div>
          <pre class="screen">find . -type f -maxdepth 1 -name '*.ext' -print0 | xargs -0 -n 1 command</pre>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">find</span>(1)</span> with "<code class="literal">-exec</code>" option with a command:
</p>
              </li>
            </ul>
          </div>
          <pre class="screen">find . -type f -maxdepth 1 -name '*.ext' -exec command '{}' \;</pre>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">find</span>(1)</span> with "<code class="literal">-exec</code>" option with a short shell script:
</p>
              </li>
            </ul>
          </div>
          <pre class="screen">find . -type f -maxdepth 1 -name '*.ext' -exec sh -c "command '{}' &amp;&amp; echo 'successful'" \;</pre>
          <p>The above examples are written to ensure proper handling of funny file names such as ones containing spaces.  See <a class="xref" href="ch10.en.html#_idioms_for_the_selection_of_files" title="10.1.5. Idioms for the selection of files">Section 10.1.5, “Idioms for the selection of files”</a> for more advance uses of <span class="citerefentry"><span class="refentrytitle">find</span>(1)</span>.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_starting_a_program_from_gui"/>9.3.10. Starting a program from GUI</h3>
              </div>
            </div>
          </div>
          <p>For the <a class="ulink" href="http://en.wikipedia.org/wiki/Command-line_interface">command-line interface (CLI)</a>, the first program with the matching name found in the directories specified in the <code class="literal">$PATH</code> environment variable is executed. See <a class="xref" href="ch01.en.html#_the_literal_path_literal_variable" title="1.5.3. The &quot;$PATH&quot; variable">Section 1.5.3, “The "<code class="literal">$PATH</code>" variable”</a>.</p>
          <p>For the <a class="ulink" href="http://en.wikipedia.org/wiki/Graphical_user_interface">graphical user interface (GUI)</a> compliant to the <a class="ulink" href="http://en.wikipedia.org/wiki/Freedesktop.org">freedesktop.org</a> standards, the <code class="literal">*.desktop</code> files in the <code class="literal">/usr/share/applications/</code> directory provide necessary attributes for the GUI menu display of each program. See <a class="xref" href="ch07.en.html#_freedesktop_org_menu" title="7.2.2. Freedesktop.org menu">Section 7.2.2, “Freedesktop.org menu”</a>.</p>
          <p>For example, the <code class="literal">chromium.desktop</code> file defines attributes for the "Chromium Web Browser" such as "Name" for the program name, "Exec" for the program execution path and arguments, "Icon" for the icon used, etc. (see the <a class="ulink" href="http://standards.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html">Desktop Entry Specification</a>) as follows:</p>
          <pre class="screen">[Desktop Entry]
Version=1.0
Name=Chromium Web Browser
GenericName=Web Browser
Comment=Access the Internet
Comment[fr]=Explorer le Web
Exec=/usr/bin/chromium %U
Terminal=false
X-MultipleArgs=false
Type=Application
Icon=chromium
Categories=Network;WebBrowser;
MimeType=text/html;text/xml;application/xhtml_xml;x-scheme-handler/http;x-scheme-handler/https;
StartupWMClass=Chromium
StartupNotify=true</pre>
          <p>This is an oversimplified description. The <code class="literal">*.desktop</code> files are scanned as follows.</p>
          <p>The desktop environment sets <code class="literal">$XDG_DATA_HOME</code> and <code class="literal">$XDG_DATA_DIR</code> environment variables.  For example, under the GNOME 3:</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><code class="literal">$XDG_DATA_HOME</code> is unset. (The default value of <code class="literal">$HOME/.local/share</code> is used.)
</p>
              </li>
              <li class="listitem">
                <p><code class="literal">$XDG_DATA_DIRS</code> is set to <code class="literal">/usr/share/gnome:/usr/local/share/:/usr/share/</code>.
</p>
              </li>
            </ul>
          </div>
          <p>So the base directories (see <a class="ulink" href="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html">XDG Base Directory Specification</a>) and the <code class="literal">applications</code> directories are as follows.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><code class="literal">$HOME/.local/share/</code><code class="literal">$HOME/.local/share/applications/</code>
</p>
              </li>
              <li class="listitem">
                <p><code class="literal">/usr/share/gnome/</code><code class="literal">/usr/share/gnome/applications/</code>
</p>
              </li>
              <li class="listitem">
                <p><code class="literal">/usr/local/share/</code><code class="literal">/usr/local/share/applications/</code>
</p>
              </li>
              <li class="listitem">
                <p><code class="literal">/usr/share/</code><code class="literal">/usr/share/applications/</code>
</p>
              </li>
            </ul>
          </div>
          <p>The <code class="literal">*.desktop</code> files are scanned in these <code class="literal">applications</code> directories in this order.</p>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>A user custom GUI menu entry can be created by adding a <code class="literal">*.desktop</code> file in the <code class="literal">$HOME/.local/share/applications/</code> directory.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Similarly, if a <code class="literal">*.desktop</code> file is created in the <code class="literal">autostart</code> directory under these base directories, the specified program in the <code class="literal">*.desktop</code> file is executed automatically when the desktop environment is started. See <a class="ulink" href="http://standards.freedesktop.org/autostart-spec/autostart-spec-latest.html">Desktop Application Autostart Specification</a>.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Similarly, if a <code class="literal">*.desktop</code> file is created in the <code class="literal">$HOME/Desktop</code> directory and the Desktop environment is configured to support the desktop icon launcher feature, the specified program in it is executed upon clicking the icon. Please note that the actual name of the <code class="literal">$HOME/Desktop</code> directory is locale dependent.  See <span class="citerefentry"><span class="refentrytitle">xdg-user-dirs-update</span>(1)</span>.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_customizing_program_to_be_started"/>9.3.11. Customizing program to be started</h3>
              </div>
            </div>
          </div>
          <p>Some programs start another program automatically.  Here are check points for customizing this process.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
Application configuration menu:
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
GNOME3 desktop: "Settings" → "System" → "Details" → "Default Applications"
</p>
                    </li>
                    <li class="listitem">
                      <p>
KDE desktop: "K" → "Control Center" → "KDE Components" → "Component Chooser"
</p>
                    </li>
                    <li class="listitem">
                      <p>
Iceweasel browser: "Edit" → "Preferences" → "Applications"
</p>
                    </li>
                    <li class="listitem">
                      <p><span class="citerefentry"><span class="refentrytitle">mc</span>(1)</span>: "<code class="literal">/etc/mc/mc.ext</code>"
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Environment variables such as "<code class="literal">$BROWSER</code>", "<code class="literal">$EDITOR</code>", "<code class="literal">$VISUAL</code>", and "<code class="literal">$PAGER</code>" (see <span class="citerefentry"><span class="refentrytitle">eviron</span>(7)</span>)
</p>
              </li>
              <li class="listitem">
                <p>
The <span class="citerefentry"><span class="refentrytitle">update-alternatives</span>(8)</span> system for programs such as "<code class="literal">editor</code>", "<code class="literal">view</code>", "<code class="literal">x-www-browser</code>", "<code class="literal">gnome-www-browser</code>", and "<code class="literal">www-browser</code>" (see <a class="xref" href="ch01.en.html#_setting_a_default_text_editor" title="1.4.7. Setting a default text editor">Section 1.4.7, “Setting a default text editor”</a>)
</p>
              </li>
              <li class="listitem">
                <p>
the "<code class="literal">~/.mailcap</code>" and "<code class="literal">/etc/mailcap</code>" file contents which associate <a class="ulink" href="http://en.wikipedia.org/wiki/MIME">MIME</a> type with program (see <span class="citerefentry"><span class="refentrytitle">mailcap</span>(5)</span>)
</p>
              </li>
              <li class="listitem">
                <p>
The "<code class="literal">~/.mime.types</code>" and "<code class="literal">/etc/mime.types</code>" file contents which associate file name extension with <a class="ulink" href="http://en.wikipedia.org/wiki/MIME">MIME</a> type (see <span class="citerefentry"><span class="refentrytitle">run-mailcap</span>(1)</span>)
</p>
              </li>
            </ul>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p><span class="citerefentry"><span class="refentrytitle">update-mime</span>(8)</span> updates the "<code class="literal">/etc/mailcap</code>" file using "<code class="literal">/etc/mailcap.order</code>" file (see <span class="citerefentry"><span class="refentrytitle">mailcap.order</span>(5)</span>).</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>The <code class="literal">debianutils</code> package provides <span class="citerefentry"><span class="refentrytitle">sensible-browser</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">sensible-editor</span>(1)</span>, and <span class="citerefentry"><span class="refentrytitle">sensible-pager</span>(1)</span> which make sensible decisions on which editor, pager, and web browser to call, respectively.  I recommend you to read these shell scripts.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>In order to run a console application such as <code class="literal">mutt</code> under X as your preferred application, you should create an X application as following and set "<code class="literal">/usr/local/bin/mutt-term</code>" as your preferred application to be started as described.</p>
                </td>
              </tr>
            </table>
          </div>
          <pre class="screen"># cat /usr/local/bin/mutt-term &lt;&lt;EOF
#!/bin/sh
gnome-terminal -e "mutt \$@"
EOF
chmod 755 /usr/local/bin/mutt-term</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_killing_a_process"/>9.3.12. Killing a process</h3>
              </div>
            </div>
          </div>
          <p>Use <span class="citerefentry"><span class="refentrytitle">kill</span>(1)</span> to kill (or send a signal to) a process by the process ID.</p>
          <p>Use <span class="citerefentry"><span class="refentrytitle">killall</span>(1)</span> or <span class="citerefentry"><span class="refentrytitle">pkill</span>(1)</span> to do the same by the process command name and other attributes.</p>
          <div class="table">
            <a id="listoffrequentlylsforkillcommand"/>
            <p class="title">
              <strong>Table 9.10. List of frequently used signals for kill command</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of frequently used signals for kill command" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    signal value
    </th>
                    <th style="text-align: left">
    signal name
    </th>
                    <th style="text-align: left">
    function
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
    1
    </td>
                    <td style="text-align: left">
    HUP
    </td>
                    <td style="text-align: left">
    restart daemon
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    15
    </td>
                    <td style="text-align: left">
    TERM
    </td>
                    <td style="text-align: left">
    normal kill
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    9
    </td>
                    <td style="text-align: left">
    KILL
    </td>
                    <td style="text-align: left">
    kill hard
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_scheduling_tasks_once"/>9.3.13. Scheduling tasks once</h3>
              </div>
            </div>
          </div>
          <p>Run the <span class="citerefentry"><span class="refentrytitle">at</span>(1)</span> command to schedule a one-time job by the following.</p>
          <pre class="screen">$ echo 'command -args'| at 3:40 monday</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_scheduling_tasks_regularly"/>9.3.14. Scheduling tasks regularly</h3>
              </div>
            </div>
          </div>
          <p>Use <span class="citerefentry"><span class="refentrytitle">cron</span>(8)</span> to schedule tasks regularly.  See <span class="citerefentry"><span class="refentrytitle">crontab</span>(1)</span> and <span class="citerefentry"><span class="refentrytitle">crontab</span>(5)</span>.</p>
          <p>You can schedule to run processes as a normal user, e.g. <code class="literal">foo</code> by creating a <span class="citerefentry"><span class="refentrytitle">crontab</span>(5)</span> file as "<code class="literal">/var/spool/cron/crontabs/foo</code>" with "<code class="literal">crontab -e</code>" command.</p>
          <p>Here is an example of a <span class="citerefentry"><span class="refentrytitle">crontab</span>(5)</span> file.</p>
          <pre class="screen"># use /bin/sh to run commands, no matter what /etc/passwd says
SHELL=/bin/sh
# mail any output to paul, no matter whose crontab this is
MAILTO=paul
# Min Hour DayOfMonth Month DayOfWeek command (Day... are OR'ed)
# run at 00:05, every day
5  0  *  * *   $HOME/bin/daily.job &gt;&gt; $HOME/tmp/out 2&gt;&amp;1
# run at 14:15 on the first of every month -- output mailed to paul
15 14 1  * *   $HOME/bin/monthly
# run at 22:00 on weekdays(1-5), annoy Joe. % for newline, last % for cc:
0 22 *   * 1-5 mail -s "It's 10pm" joe%Joe,%%Where are your kids?%.%%
23 */2 1 2 *   echo "run 23 minutes after 0am, 2am, 4am ..., on Feb 1"
5  4 *   * sun echo "run at 04:05 every Sunday"
# run at 03:40 on the first Monday of each month
40 3 1-7 * *   [ "$(date +%a)" == "Mon" ] &amp;&amp; command -args</pre>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>For the system not running continuously, install the <code class="literal">anacron</code> package to schedule periodic commands at the specified intervals as closely as machine-uptime permits.  See <span class="citerefentry"><span class="refentrytitle">anacron</span>(8)</span> and <span class="citerefentry"><span class="refentrytitle">anacrontab</span>(5)</span>.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>For scheduled system maintenance scripts, you can run them periodically from root account by placing such scripts in "<code class="literal">/etc/cron.hourly/</code>", "<code class="literal">/etc/cron.daily/</code>", "<code class="literal">/etc/cron.weekly/</code>", or "<code class="literal">/etc/cron.monthly/</code>".  Execution timings of these scripts can be customized by "<code class="literal">/etc/crontab</code>" and "<code class="literal">/etc/anacrontab</code>".</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_alt_sysrq_key"/>9.3.15. Alt-SysRq key</h3>
              </div>
            </div>
          </div>
          <p>Insurance against system malfunction is provided by the kernel compile option "Magic SysRq key" (<a class="ulink" href="http://en.wikipedia.org/wiki/Secure_attention_key">SAK</a> key) which is now the default for the Debian kernel.  Pressing Alt-SysRq followed by one of the following keys does the magic of rescuing control of the system.</p>
          <div class="table">
            <a id="listofsakcommandkeys"/>
            <p class="title">
              <strong>Table 9.11. List of SAK command keys</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of SAK command keys" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    key following Alt-SysRq
    </th>
                    <th style="text-align: left">
    description of action
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">r</code>
                </td>
                    <td style="text-align: left">
    restore the keyboard from <span class="strong"><strong>r</strong></span>aw mode after X crashes
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">0</code>
                </td>
                    <td style="text-align: left">
    change the console loglevel to <span class="strong"><strong>0</strong></span> to reduce error messages
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">k</code>
                </td>
                    <td style="text-align: left"><span class="strong"><strong>k</strong></span>ill all processes on the <span class="strong"><strong>current virtual console</strong></span></td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">e</code>
                </td>
                    <td style="text-align: left">
    send a SIGT<span class="strong"><strong>E</strong></span>RM to all processes, except for <span class="citerefentry"><span class="refentrytitle">init</span>(8)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">i</code>
                </td>
                    <td style="text-align: left">
    send a SIGK<span class="strong"><strong>I</strong></span>LL to all processes, except for <span class="citerefentry"><span class="refentrytitle">init</span>(8)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">s</code>
                </td>
                    <td style="text-align: left"><span class="strong"><strong>s</strong></span>ync all mounted filesystems to avoid data corruption
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">u</code>
                </td>
                    <td style="text-align: left">
    remount all mounted filesystems read-only (<span class="strong"><strong>u</strong></span>mount)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                  <code class="literal">b</code>
                </td>
                    <td style="text-align: left">
    re<span class="strong"><strong>b</strong></span>oot the system without syncing or unmounting
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Read the <span class="citerefentry"><span class="refentrytitle">signal</span>(7)</span>, <span class="citerefentry"><span class="refentrytitle">kill</span>(1)</span>, and <span class="citerefentry"><span class="refentrytitle">sync</span>(1)</span> manpages to understand the description above.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>The combination of "Alt-SysRq s", "Alt-SysRq u", and "Alt-SysRq r" is good for getting out of really bad situations and gaining usable keyboard access without stopping the system.</p>
          <p>See "<code class="literal">/usr/share/doc/linux-doc-3.*/Documentation/sysrq.txt.gz</code>".</p>
          <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Caution">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Caution]" src="images/caution.png"/>
                </td>
                <th align="left">Caution</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>The Alt-SysRq feature may be considered a security risk by allowing users access to root-privileged functions.  Placing "<code class="literal">echo 0 &gt;/proc/sys/kernel/sysrq</code>" in "<code class="literal">/etc/rc.local</code>" or "<code class="literal">kernel.sysrq = 0</code>" in "<code class="literal">/etc/sysctl.conf</code>" disables the Alt-SysRq feature.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>From SSH terminal etc., you can use the Alt-SysRq feature by writing to the "<code class="literal">/proc/sysrq-trigger</code>". For example, "<code class="literal">echo s &gt; /proc/sysrq-trigger; echo u &gt; /proc/sysrq-trigger</code>" from the root shell prompt <span class="strong"><strong>s</strong></span>yncs and <span class="strong"><strong>u</strong></span>mounts all mounted filesystems.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
      </div>
      <div class="section">
        <div class="titlepage">
          <div>
            <div>
              <h2 class="title"><a id="_system_maintenance_tips"/>9.4. System maintenance tips</h2>
            </div>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_who_is_on_the_system"/>9.4.1. Who is on the system?</h3>
              </div>
            </div>
          </div>
          <p>You can check who is on the system by the following.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">who</span>(1)</span>   shows who is logged on.
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">w</span>(1)</span>     shows who is logged on and what they are doing.
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">last</span>(1)</span>  shows listing of last logged in user.
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">lastb</span>(1)</span> shows listing of last bad logged in users.
</p>
              </li>
            </ul>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>"<code class="literal">/var/run/utmp</code>", and "<code class="literal">/var/log/wtmp</code>" hold such user information.  See <span class="citerefentry"><span class="refentrytitle">login</span>(1)</span> and <span class="citerefentry"><span class="refentrytitle">utmp</span>(5)</span>.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_warning_everyone"/>9.4.2. Warning everyone</h3>
              </div>
            </div>
          </div>
          <p>You can send message to everyone who is logged on to the system with <span class="citerefentry"><span class="refentrytitle">wall</span>(1)</span> by the following.</p>
          <pre class="screen">$ echo "We are shutting down in 1 hour" | wall</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_hardware_identification"/>9.4.3. Hardware identification</h3>
              </div>
            </div>
          </div>
          <p>For the <a class="ulink" href="http://en.wikipedia.org/wiki/Peripheral_Component_Interconnect">PCI</a>-like devices (<a class="ulink" href="http://en.wikipedia.org/wiki/Accelerated_Graphics_Port">AGP</a>, <a class="ulink" href="http://en.wikipedia.org/wiki/PCI_Express">PCI-Express</a>, <a class="ulink" href="http://en.wikipedia.org/wiki/PC_Card#CardBus">CardBus</a>, <a class="ulink" href="http://en.wikipedia.org/wiki/ExpressCard">ExpressCard</a>, etc.), <span class="citerefentry"><span class="refentrytitle">lspci</span>(8)</span> (probably with "<code class="literal">-nn</code>" option) is a good start for the hardware identification.</p>
          <p>Alternatively, you can identify the hardware by reading contents of "<code class="literal">/proc/bus/pci/devices</code>" or browsing directory tree under "<code class="literal">/sys/bus/pci</code>" (see <a class="xref" href="ch01.en.html#_procfs_and_sysfs" title="1.2.12. procfs and sysfs">Section 1.2.12, “procfs and sysfs”</a>).</p>
          <div class="table">
            <a id="listofhardwareidntificationtools"/>
            <p class="title">
              <strong>Table 9.12. List of hardware identification tools</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of hardware identification tools" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/pciutils">
                  <code class="literal">pciutils</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=pciutils">V:167, I:992</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/p/pciutils.html">1220</a>
                    </td>
                    <td style="text-align: left">
    Linux PCI Utilities: <span class="citerefentry"><span class="refentrytitle">lspci</span>(8)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/usbutils">
                  <code class="literal">usbutils</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=usbutils">V:97, I:862</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/u/usbutils.html">721</a>
                    </td>
                    <td style="text-align: left">
    Linux USB utilities: <span class="citerefentry"><span class="refentrytitle">lsusb</span>(8)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/pcmciautils">
                  <code class="literal">pcmciautils</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=pcmciautils">V:22, I:52</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/p/pcmciautils.html">94</a>
                    </td>
                    <td style="text-align: left">
    PCMCIA utilities for Linux: <span class="citerefentry"><span class="refentrytitle">pccardctl</span>(8)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/scsitools">
                  <code class="literal">scsitools</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=scsitools">V:0, I:4</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/scsitools.html">366</a>
                    </td>
                    <td style="text-align: left">
    collection of tools for SCSI hardware management: <span class="citerefentry"><span class="refentrytitle">lsscsi</span>(8)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/procinfo">
                  <code class="literal">procinfo</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=procinfo">V:1, I:16</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/p/procinfo.html">186</a>
                    </td>
                    <td style="text-align: left">
    system information obtained from "<code class="literal">/proc</code>": <span class="citerefentry"><span class="refentrytitle">lsdev</span>(8)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/lshw">
                  <code class="literal">lshw</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=lshw">V:9, I:85</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/l/lshw.html">671</a>
                    </td>
                    <td style="text-align: left">
    information about hardware configuration: <span class="citerefentry"><span class="refentrytitle">lshw</span>(1)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/discover">
                  <code class="literal">discover</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=discover">V:39, I:927</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/discover.html">90</a>
                    </td>
                    <td style="text-align: left">
    hardware identification system: <span class="citerefentry"><span class="refentrytitle">discover</span>(8)</span>
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_hardware_configuration"/>9.4.4. Hardware configuration</h3>
              </div>
            </div>
          </div>
          <p>Although most of the hardware configuration on modern GUI desktop systems such as GNOME and KDE can be managed through accompanying GUI configuration tools, it is a good idea to know some basics methods to configure them.</p>
          <div class="table">
            <a id="listofhardwareconfigurationtools"/>
            <p class="title">
              <strong>Table 9.13. List of hardware configuration tools</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of hardware configuration tools" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/console-setup">
                  <code class="literal">console-setup</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=console-setup">V:450, I:933</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/c/console-setup.html">437</a>
                    </td>
                    <td style="text-align: left">
    Linux console font and keytable utilities
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/x11-xserver-utils">
                  <code class="literal">x11-xserver-utils</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=x11-xserver-utils">V:364, I:585</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/x/x11-xserver-utils.html">516</a>
                    </td>
                    <td style="text-align: left">
    X server utilities: <span class="citerefentry"><span class="refentrytitle">xset</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">xmodmap</span>(1)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/acpid">
                  <code class="literal">acpid</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=acpid">V:508, I:895</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/a/acpid.html">143</a>
                    </td>
                    <td style="text-align: left">
    daemon to manage events delivered by the Advanced Configuration and Power Interface (ACPI)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/acpi">
                  <code class="literal">acpi</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=acpi">V:38, I:863</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/a/acpi.html">46</a>
                    </td>
                    <td style="text-align: left">
    utility to display information on ACPI devices
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/apmd">
                  <code class="literal">apmd</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=apmd">V:0, I:9</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/a/apmd.html">132</a>
                    </td>
                    <td style="text-align: left">
    daemon to manage events delivered by the Advanced Power Management (APM)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/sleepd">
                  <code class="literal">sleepd</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=sleepd">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/sleepd.html">79</a>
                    </td>
                    <td style="text-align: left">
    daemon to put a laptop to sleep during inactivity
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/hdparm">
                  <code class="literal">hdparm</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=hdparm">V:238, I:395</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/h/hdparm.html">237</a>
                    </td>
                    <td style="text-align: left">
    hard disk access optimization (see <a class="xref" href="ch09.en.html#_optimization_of_hard_disk" title="9.5.9. Optimization of hard disk">Section 9.5.9, “Optimization of hard disk”</a>)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/smartmontools">
                  <code class="literal">smartmontools</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=smartmontools">V:112, I:194</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/smartmontools.html">1716</a>
                    </td>
                    <td style="text-align: left">
    control and monitor storage systems using <a class="ulink" href="http://en.wikipedia.org/wiki/S.M.A.R.T.">S.M.A.R.T.</a>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/setserial">
                  <code class="literal">setserial</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=setserial">V:5, I:12</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/setserial.html">113</a>
                    </td>
                    <td style="text-align: left">
    collection of tools for serial port management
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/memtest86+">
                  <code class="literal">memtest86+</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=memtest86+">V:1, I:38</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/m/memtest86+.html">2391</a>
                    </td>
                    <td style="text-align: left">
    collection of tools for memory hardware management
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/scsitools">
                  <code class="literal">scsitools</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=scsitools">V:0, I:4</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/scsitools.html">366</a>
                    </td>
                    <td style="text-align: left">
    collection of tools for <a class="ulink" href="http://en.wikipedia.org/wiki/SCSI">SCSI</a> hardware management
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/setcd">
                  <code class="literal">setcd</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=setcd">V:0, I:1</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/setcd.html">35</a>
                    </td>
                    <td style="text-align: left">
    compact disc drive access optimization
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/big-cursor">
                  <code class="literal">big-cursor</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=big-cursor">I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/b/big-cursor.html">27</a>
                    </td>
                    <td style="text-align: left">
    larger mouse cursors for X
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <p>Here, <a class="ulink" href="http://en.wikipedia.org/wiki/Advanced_Configuration_and_Power_Interface">ACPI</a> is a newer framework for the power management system than <a class="ulink" href="http://en.wikipedia.org/wiki/Advanced_Power_Management">APM</a>.</p>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>CPU frequency scaling on modern system is governed by kernel modules such as <code class="literal">acpi_cpufreq</code>.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_system_and_hardware_time"/>9.4.5. System and hardware time</h3>
              </div>
            </div>
          </div>
          <p>The following sets system and hardware time to MM/DD hh:mm, CCYY.</p>
          <pre class="screen"># date MMDDhhmmCCYY
# hwclock --utc --systohc
# hwclock --show</pre>
          <p>Times are normally displayed in the local time on the Debian system but the hardware and system time usually use <a class="ulink" href="http://en.wikipedia.org/wiki/UTC">UTC(GMT)</a>.</p>
          <p>If the hardware (BIOS) time is set to UTC, change the setting to "<code class="literal">UTC=yes</code>" in the "<code class="literal">/etc/default/rcS</code>".</p>
          <p>The following reconfigure the timezone used by the Debian system.</p>
          <pre class="screen"># dpkg-reconfigure tzdata</pre>
          <p>If you wish to update system time via network, consider to use the <a class="ulink" href="http://en.wikipedia.org/wiki/Network_Time_Protocol">NTP</a> service with the packages such as <code class="literal">ntp</code>, <code class="literal">ntpdate</code>, and <code class="literal">chrony</code>.</p>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Under <a class="ulink" href="http://en.wikipedia.org/wiki/Systemd">systemd</a>, use <code class="literal">systemd-timesyncd</code> for the network time synchronization instead.  See <span class="citerefentry"><span class="refentrytitle">systemd-timesyncd</span>(8)</span>.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>See the following.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
              <a class="ulink" href="http://www.tldp.org/HOWTO/TimePrecision-HOWTO/index.html">Managing Accurate Date and Time HOWTO</a>
            </p>
              </li>
              <li class="listitem">
                <p>
              <a class="ulink" href="http://www.ntp.org/">NTP Public Services Project</a>
            </p>
              </li>
              <li class="listitem">
                <p>
The <code class="literal">ntp-doc</code> package
</p>
              </li>
            </ul>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p><span class="citerefentry"><span class="refentrytitle">ntptrace</span>(8)</span> in the <code class="literal">ntp</code> package can trace a chain of NTP servers back to the primary source.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_the_terminal_configuration"/>9.4.6. The terminal configuration</h3>
              </div>
            </div>
          </div>
          <p>There are several components to configure character console and <span class="citerefentry"><span class="refentrytitle">ncurses</span>(3)</span> system features.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
The "<code class="literal">/etc/terminfo/*/*</code>" file (<span class="citerefentry"><span class="refentrytitle">terminfo</span>(5)</span>)
</p>
              </li>
              <li class="listitem">
                <p>
The "<code class="literal">$TERM</code>" environment variable (<span class="citerefentry"><span class="refentrytitle">term</span>(7)</span>)
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">setterm</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">stty</span>(1)</span>, <span class="citerefentry"><span class="refentrytitle">tic</span>(1)</span>, and <span class="citerefentry"><span class="refentrytitle">toe</span>(1)</span>
</p>
              </li>
            </ul>
          </div>
          <p>If the <code class="literal">terminfo</code> entry for <code class="literal">xterm</code> doesn't work with a non-Debian <code class="literal">xterm</code>, change your terminal type, "<code class="literal">$TERM</code>", from "<code class="literal">xterm</code>" to one of the feature-limited versions such as "<code class="literal">xterm-r6</code>" when you log in to a Debian system remotely.  See "<code class="literal">/usr/share/doc/libncurses5/FAQ</code>" for more.  "<code class="literal">dumb</code>" is the lowest common denominator for "<code class="literal">$TERM</code>".</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_the_sound_infrastructure"/>9.4.7. The sound infrastructure</h3>
              </div>
            </div>
          </div>
          <p>Device drivers for sound cards for current Linux are provided by <a class="ulink" href="http://en.wikipedia.org/wiki/Advanced_Linux_Sound_Architecture">Advanced Linux Sound Architecture (ALSA)</a>.  ALSA provides emulation mode for previous <a class="ulink" href="http://en.wikipedia.org/wiki/Open_Sound_System">Open Sound System (OSS)</a> for compatibility.</p>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Use "<code class="literal">cat /dev/urandom &gt; /dev/audio</code>" or <span class="citerefentry"><span class="refentrytitle">speaker-test</span>(1)</span> to test speaker (^C to stop).</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>If you can not get sound, your speaker may be connected to a muted output.  Modern sound system has many outputs.  <span class="citerefentry"><span class="refentrytitle">alsamixer</span>(1)</span> in the <code class="literal">alsa-utils</code> package is useful to configure volume and mute settings.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>Application softwares may be configured not only to access sound devices directly but also to access them via some standardized sound server system.</p>
          <div class="table">
            <a id="listofsoundpackages"/>
            <p class="title">
              <strong>Table 9.14. List of sound packages</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of sound packages" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/alsa-base">
                  <code class="literal">alsa-base</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=alsa-base">I:463</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/a/alsa-base.html">NOT_FOUND</a>
                    </td>
                    <td style="text-align: left">
    ALSA driver configuration files
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/alsa-utils">
                  <code class="literal">alsa-utils</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=alsa-utils">V:379, I:532</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/a/alsa-utils.html">2103</a>
                    </td>
                    <td style="text-align: left">
    utilities for configuring and using ALSA
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/oss-compat">
                  <code class="literal">oss-compat</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=oss-compat">V:4, I:46</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/o/oss-compat.html">7</a>
                    </td>
                    <td style="text-align: left">
    OSS compatibility under ALSA preventing "<code class="literal">/dev/dsp not found</code>" errors
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/jackd">
                  <code class="literal">jackd</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=jackd">V:3, I:27</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/j/jackd.html">32</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/JACK_Audio_Connection_Kit">JACK Audio Connection Kit. (JACK)</a> server (low latency)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/libjack0">
                  <code class="literal">libjack0</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=libjack0">V:0, I:19</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/libj/libjack0.html">135</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/JACK_Audio_Connection_Kit">JACK Audio Connection Kit. (JACK)</a> library (low latency)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/nas">
                  <code class="literal">nas</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=nas">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/n/nas.html">240</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/Network_Audio_System">Network Audio System (NAS)</a> server
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/libaudio2">
                  <code class="literal">libaudio2</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=libaudio2">V:60, I:562</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/liba/libaudio2.html">162</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/Network_Audio_System">Network Audio System (NAS)</a>  library
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/pulseaudio">
                  <code class="literal">pulseaudio</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=pulseaudio">V:358, I:498</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/p/pulseaudio.html">5858</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/PulseAudio">PulseAudio</a> server, replacement for ESD
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/libpulse0">
                  <code class="literal">libpulse0</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=libpulse0">V:250, I:654</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/libp/libpulse0.html">955</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/PulseAudio">PulseAudio</a> client library, replacement for ESD
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/libgstreamer1.0-0">
                  <code class="literal">libgstreamer1.0-0</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=libgstreamer1.0-0">V:227, I:485</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/libg/libgstreamer1.0-0.html">4742</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/GStreamer">GStreamer</a>: GNOME sound engine
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/libphonon4">
                  <code class="literal">libphonon4</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=libphonon4">I:224</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/libp/libphonon4.html">588</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/Phonon_(KDE)">Phonon</a>: KDE sound engine
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <p>There is usually a common sound engine for each popular desktop environment. Each sound engine used by the application can choose to connect to different sound servers.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_disabling_the_screen_saver"/>9.4.8. Disabling the screen saver</h3>
              </div>
            </div>
          </div>
          <p>For disabling the screen saver, use following commands.</p>
          <div class="table">
            <a id="listofcommandsfongthescreensaver"/>
            <p class="title">
              <strong>Table 9.15. List of commands for disabling the screen saver</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of commands for disabling the screen saver" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    environment
    </th>
                    <th style="text-align: left">
    command
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
    The Linux console
    </td>
                    <td style="text-align: left">
                  <code class="literal">setterm -powersave off</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    The X Window (turning off screensaver)
    </td>
                    <td style="text-align: left">
                  <code class="literal">xset s off</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    The X Window (disabling dpms)
    </td>
                    <td style="text-align: left">
                  <code class="literal">xset -dpms</code>
                </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    The X Window (GUI configuration of screen saver)
    </td>
                    <td style="text-align: left">
                  <code class="literal">xscreensaver-command -prefs</code>
                </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_disabling_beep_sounds"/>9.4.9. Disabling beep sounds</h3>
              </div>
            </div>
          </div>
          <p>One can always unplug the PC speaker to disable beep sounds.  Removing <code class="literal">pcspkr</code> kernel module does this for you.</p>
          <p>The following prevents the <span class="citerefentry"><span class="refentrytitle">readline</span>(3)</span> program used by <span class="citerefentry"><span class="refentrytitle">bash</span>(1)</span> to beep when encountering an alert character (ASCII=7).</p>
          <pre class="screen">$ echo "set bell-style none"&gt;&gt; ~/.inputrc</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_memory_usage"/>9.4.10. Memory usage</h3>
              </div>
            </div>
          </div>
          <p>There are 2 resources available for you to get the memory usage situation.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
The kernel boot message in the "<code class="literal">/var/log/dmesg</code>" contains the total exact size of available memory.
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">free</span>(1)</span> and <span class="citerefentry"><span class="refentrytitle">top</span>(1)</span> display information on memory resources on the running system.
</p>
              </li>
            </ul>
          </div>
          <p>Here is an example.</p>
          <pre class="screen"># grep '\] Memory' /var/log/dmesg
[    0.004000] Memory: 990528k/1016784k available (1975k kernel code, 25868k reserved, 931k data, 296k init)
$ free -k
             total       used       free     shared    buffers     cached
Mem:        997184     976928      20256          0     129592     171932
-/+ buffers/cache:     675404     321780
Swap:      4545576          4    4545572</pre>
          <p>You may be wondering "dmesg tells me a free of 990 MB, and free -k says 320 MB is free. More than 600 MB missing …".</p>
          <p>Do not worry about the large size of "<code class="literal">used</code>" and the small size of "<code class="literal">free</code>" in the "<code class="literal">Mem:</code>" line, but read the one under them (675404 and 321780 in the example above) and relax.</p>
          <p>For my MacBook with 1GB=1048576k DRAM (video system steals some of this), I see the following.</p>
          <div class="table">
            <a id="listofmemorysizesreported"/>
            <p class="title">
              <strong>Table 9.16. List of memory sizes reported</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of memory sizes reported" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    report
    </th>
                    <th style="text-align: left">
    size
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
    Total size in dmesg
    </td>
                    <td style="text-align: left">
    1016784k = 1GB - 31792k
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    Free in dmesg
    </td>
                    <td style="text-align: left">
    990528k
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    Total under shell
    </td>
                    <td style="text-align: left">
    997184k
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
    Free under shell
    </td>
                    <td style="text-align: left">
    20256k (but effectively 321780k)
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_system_security_and_integrity_check"/>9.4.11. System security and integrity check</h3>
              </div>
            </div>
          </div>
          <p>Poor system maintenance may expose your system to external exploitation.</p>
          <p>For system security and integrity check, you should start with the following.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
The <code class="literal">debsums</code> package, see <span class="citerefentry"><span class="refentrytitle">debsums</span>(1)</span> and <a class="xref" href="ch02.en.html#_top_level_release_file_and_authenticity" title="2.5.2. Top level &quot;Release&quot; file and authenticity">Section 2.5.2, “Top level "Release" file and authenticity”</a>.
</p>
              </li>
              <li class="listitem">
                <p>
The <code class="literal">chkrootkit</code> package, see <span class="citerefentry"><span class="refentrytitle">chkrootkit</span>(1)</span>.
</p>
              </li>
              <li class="listitem">
                <p>
The <code class="literal">clamav</code> package family, see <span class="citerefentry"><span class="refentrytitle">clamscan</span>(1)</span> and <span class="citerefentry"><span class="refentrytitle">freshclam</span>(1)</span>.
</p>
              </li>
              <li class="listitem">
                <p><a class="ulink" href="http://www.debian.org/security/faq">Debian security FAQ</a>.
</p>
              </li>
              <li class="listitem">
                <p><a class="ulink" href="http://www.debian.org/doc/manuals/securing-debian-howto/">Securing Debian Manual</a>.
</p>
              </li>
            </ul>
          </div>
          <div class="table">
            <a id="listoftoolsforsyndintegritycheck"/>
            <p class="title">
              <strong>Table 9.17. List of tools for system security and integrity check</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of tools for system security and integrity check" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/logcheck">
                  <code class="literal">logcheck</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=logcheck">V:12, I:14</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/l/logcheck.html">152</a>
                    </td>
                    <td style="text-align: left">
    daemon to mail anomalies in the system logfiles to the administrator
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/debsums">
                  <code class="literal">debsums</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=debsums">V:5, I:38</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/debsums.html">120</a>
                    </td>
                    <td style="text-align: left">
    utility to verify installed package files against MD5 checksums
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/chkrootkit">
                  <code class="literal">chkrootkit</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=chkrootkit">V:7, I:28</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/c/chkrootkit.html">951</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/Rootkit">rootkit</a> detector
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/clamav">
                  <code class="literal">clamav</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=clamav">V:16, I:71</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/c/clamav.html">874</a>
                    </td>
                    <td style="text-align: left">
    anti-virus utility for Unix - command-line interface
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/tiger">
                  <code class="literal">tiger</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=tiger">V:3, I:4</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/t/tiger.html">2599</a>
                    </td>
                    <td style="text-align: left">
    report system security vulnerabilities
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/tripwire">
                  <code class="literal">tripwire</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=tripwire">V:3, I:4</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/t/tripwire.html">11480</a>
                    </td>
                    <td style="text-align: left">
    file and directory integrity checker
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/john">
                  <code class="literal">john</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=john">V:3, I:14</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/j/john.html">449</a>
                    </td>
                    <td style="text-align: left">
    active password cracking tool
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/aide">
                  <code class="literal">aide</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=aide">V:1, I:2</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/a/aide.html">2002</a>
                    </td>
                    <td style="text-align: left">
    Advanced Intrusion Detection Environment - static binary
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/integrit">
                  <code class="literal">integrit</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=integrit">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/i/integrit.html">313</a>
                    </td>
                    <td style="text-align: left">
    file integrity verification program
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/crack">
                  <code class="literal">crack</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=crack">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/c/crack.html">128</a>
                    </td>
                    <td style="text-align: left">
    password guessing program
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <p>Here is a simple script to check for typical world writable incorrect file permissions.</p>
          <pre class="screen"># find / -perm 777 -a \! -type s -a \! -type l -a \! \( -type d -a -perm 1777 \)</pre>
          <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Caution">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Caution]" src="images/caution.png"/>
                </td>
                <th align="left">Caution</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Since the <code class="literal">debsums</code> package uses <a class="ulink" href="http://en.wikipedia.org/wiki/MD5">MD5</a> checksums stored locally, it can not be fully trusted as the system security audit tool against malicious attacks.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
      </div>
      <div class="section">
        <div class="titlepage">
          <div>
            <div>
              <h2 class="title"><a id="_data_storage_tips"/>9.5. Data storage tips</h2>
            </div>
          </div>
        </div>
        <p>Booting your system with Linux <a class="ulink" href="http://en.wikipedia.org/wiki/Live_CD">live CDs</a> or <a class="ulink" href="http://www.debian.org/releases/stable/debian-installer/">debian-installer CDs</a> in rescue mode makes it easy for you to reconfigure data storage on your boot device.</p>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_disk_space_usage"/>9.5.1. Disk space usage</h3>
              </div>
            </div>
          </div>
          <p>The disk space usage can be evaluated by programs provided by the <code class="literal">mount</code>, <code class="literal">coreutils</code>, and <code class="literal">xdu</code> packages:</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">mount</span>(8)</span> reports all mounted filesystems (= disks).
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">df</span>(1)</span> reports the disk space usage for the file system.
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">du</span>(1)</span> reports the disk space usage for the directory tree.
</p>
              </li>
            </ul>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You can feed the output of <span class="citerefentry"><span class="refentrytitle">du</span>(8)</span> to <span class="citerefentry"><span class="refentrytitle">xdu</span>(1x)</span> to produce its graphical and interactive presentation with "<code class="literal">du -k . |xdu</code>", "<code class="literal">sudo du -k -x / |xdu</code>", etc.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_disk_partition_configuration"/>9.5.2. Disk partition configuration</h3>
              </div>
            </div>
          </div>
          <p>For <a class="ulink" href="http://en.wikipedia.org/wiki/Disk_partitioning">disk partition</a> configuration, although <span class="citerefentry"><span class="refentrytitle">fdisk</span>(8)</span> has been considered standard, <span class="citerefentry"><span class="refentrytitle">parted</span>(8)</span> deserves some attention.  "Disk partitioning data", "partition table", "partition map", and "disk label" are all synonyms.</p>
          <p>Most PCs use the classic <a class="ulink" href="http://en.wikipedia.org/wiki/Master_boot_record">Master Boot Record (MBR)</a> scheme to hold <a class="ulink" href="http://en.wikipedia.org/wiki/Disk_partitioning">disk partitioning</a> data in the first sector, i.e., <a class="ulink" href="http://en.wikipedia.org/wiki/Logical_block_addressing">LBA</a> sector 0 (512 bytes).</p>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Some new PCs with <a class="ulink" href="http://en.wikipedia.org/wiki/Extensible_Firmware_Interface">Extensible Firmware Interface (EFI)</a>, including Intel-based Macs, use <a class="ulink" href="http://en.wikipedia.org/wiki/GUID_Partition_Table">GUID Partition Table (GPT)</a> scheme to hold <a class="ulink" href="http://en.wikipedia.org/wiki/Disk_partitioning">disk partitioning</a> data not in the first sector.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>Although <span class="citerefentry"><span class="refentrytitle">fdisk</span>(8)</span> has been standard for the disk partitioning tool, <span class="citerefentry"><span class="refentrytitle">parted</span>(8)</span> is replacing it.</p>
          <div class="table">
            <a id="listofdiskpartitnagementpackages"/>
            <p class="title">
              <strong>Table 9.18. List of disk partition management packages</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of disk partition management packages" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    GPT
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/util-linux">
                  <code class="literal">util-linux</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=util-linux">V:879, I:999</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/u/util-linux.html">3558</a>
                    </td>
                    <td style="text-align: left">
    Not supported
    </td>
                    <td style="text-align: left">
    miscellaneous system utilities including <span class="citerefentry"><span class="refentrytitle">fdisk</span>(8)</span> and <span class="citerefentry"><span class="refentrytitle">cfdisk</span>(8)</span>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/parted">
                  <code class="literal">parted</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=parted">V:340, I:544</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/p/parted.html">278</a>
                    </td>
                    <td style="text-align: left">
    Supported
    </td>
                    <td style="text-align: left">
    GNU Parted disk partition resizing program
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/gparted">
                  <code class="literal">gparted</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=gparted">V:25, I:147</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/g/gparted.html">6788</a>
                    </td>
                    <td style="text-align: left">
    Supported
    </td>
                    <td style="text-align: left">
    GNOME partition editor based on <code class="literal">libparted</code>
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/gdisk">
                  <code class="literal">gdisk</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=gdisk">V:16, I:471</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/g/gdisk.html">746</a>
                    </td>
                    <td style="text-align: left">
    Supported
    </td>
                    <td style="text-align: left">
    partition editor for the GPT disk
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/kpartx">
                  <code class="literal">kpartx</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=kpartx">V:13, I:28</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/k/kpartx.html">75</a>
                    </td>
                    <td style="text-align: left">
    Supported
    </td>
                    <td style="text-align: left">
    program to create device mappings for partitions
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Caution">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Caution]" src="images/caution.png"/>
                </td>
                <th align="left">Caution</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Although <span class="citerefentry"><span class="refentrytitle">parted</span>(8)</span> claims to create and to resize filesystem too, it is safer to do such things using best maintained specialized tools such as <span class="citerefentry"><span class="refentrytitle">mkfs</span>(8)</span> (<span class="citerefentry"><span class="refentrytitle">mkfs.msdos</span>(8)</span>, <span class="citerefentry"><span class="refentrytitle">mkfs.ext2</span>(8)</span>, <span class="citerefentry"><span class="refentrytitle">mkfs.ext3</span>(8)</span>, <span class="citerefentry"><span class="refentrytitle">mkfs.ext4</span>(8)</span>, …) and <span class="citerefentry"><span class="refentrytitle">resize2fs</span>(8)</span>.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>In order to switch between <a class="ulink" href="http://en.wikipedia.org/wiki/GUID_Partition_Table">GPT</a> and <a class="ulink" href="http://en.wikipedia.org/wiki/Master_boot_record">MBR</a>, you need to erase first few blocks of disk contents directly (see <a class="xref" href="ch09.en.html#_clearing_file_contents" title="9.7.6. Clearing file contents">Section 9.7.6, “Clearing file contents”</a>) and use "<code class="literal">parted /dev/sdx mklabel gpt</code>" or "<code class="literal">parted /dev/sdx mklabel msdos</code>" to set it.  Please note "<code class="literal">msdos</code>" is use here for <a class="ulink" href="http://en.wikipedia.org/wiki/Master_boot_record">MBR</a>.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_accessing_partition_using_uuid"/>9.5.3. Accessing partition using UUID</h3>
              </div>
            </div>
          </div>
          <p>Although reconfiguration of your partition or activation order of removable storage media may yield different names for partitions, you can access them consistently. This is also helpful if you have multiple disks and your BIOS doesn't give them consistent device names.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">mount</span>(8)</span> with "<code class="literal">-U</code>" option can mount a block device using <a class="ulink" href="http://en.wikipedia.org/wiki/Universally_Unique_Identifier">UUID</a>, instead of using its file name such as "<code class="literal">/dev/sda3</code>".
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">/etc/fstab</code>" (see <span class="citerefentry"><span class="refentrytitle">fstab</span>(5)</span>) can use <a class="ulink" href="http://en.wikipedia.org/wiki/Universally_Unique_Identifier">UUID</a>.
</p>
              </li>
              <li class="listitem">
                <p>
Boot loaders (<a class="xref" href="ch03.en.html#_stage_2_the_boot_loader" title="3.1.2. Stage 2: the boot loader">Section 3.1.2, “Stage 2: the boot loader”</a>) may use <a class="ulink" href="http://en.wikipedia.org/wiki/Universally_Unique_Identifier">UUID</a> too.
</p>
              </li>
            </ul>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You can probe <a class="ulink" href="http://en.wikipedia.org/wiki/Universally_Unique_Identifier">UUID</a> of a block special device with <span class="citerefentry"><span class="refentrytitle">blkid</span>(8)</span>.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Device nodes of devices such as removable storage media can be made static by using <a class="ulink" href="http://www.reactivated.net/writing_udev_rules.html">udev rules</a>, if needed.  See <a class="xref" href="ch03.en.html#_the_udev_system" title="3.3. The udev system">Section 3.3, “The udev system”</a>.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_lvm2"/>9.5.4. LVM2</h3>
              </div>
            </div>
          </div>
          <p>LVM2 is a <a class="ulink" href="http://en.wikipedia.org/wiki/Logical_Volume_Manager_(Linux)">logical volume manager</a> for the Linux kernel.  With LVM2, disk partitions can be created on logical volumes instead of the physical harddisks.</p>
          <p>LVM requires the following.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
device-mapper support in the Linux kernel (default for Debian kernels)
</p>
              </li>
              <li class="listitem">
                <p>
the userspace device-mapper support library (<code class="literal">libdevmapper*</code> package)
</p>
              </li>
              <li class="listitem">
                <p>
the userspace LVM2 tools (<code class="literal">lvm2</code> package)
</p>
              </li>
            </ul>
          </div>
          <p>Please start learning LVM2 from the following manpages.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">lvm</span>(8)</span>: Basics of LVM2 mechanism (list of all LVM2 commands)
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">lvm.conf</span>(5)</span>: Configuration file for LVM2
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">lvs</span>(8)</span>: Report information about logical volumes
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">vgs</span>(8)</span>: Report information about volume groups
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">pvs</span>(8)</span>: Report information about physical volumes
</p>
              </li>
            </ul>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_filesystem_configuration"/>9.5.5. Filesystem configuration</h3>
              </div>
            </div>
          </div>
          <p>For <a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">ext4</a> filesystem, the <code class="literal">e2fsprogs</code> package provides the following.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">mkfs.ext4</span>(8)</span> to create new <a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">ext4</a> filesystem
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">fsck.ext4</span>(8)</span> to check and to repair existing <a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">ext4</a> filesystem
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">tune2fs</span>(8)</span> to configure superblock of <a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">ext4</a> filesystem
</p>
              </li>
              <li class="listitem">
                <p><span class="citerefentry"><span class="refentrytitle">debugfs</span>(8)</span> to debug <a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">ext4</a> filesystem interactively. (It has <code class="literal">undel</code> command to recover deleted files.)
</p>
              </li>
            </ul>
          </div>
          <p>The <span class="citerefentry"><span class="refentrytitle">mkfs</span>(8)</span> and <span class="citerefentry"><span class="refentrytitle">fsck</span>(8)</span> commands are provided by the <code class="literal">e2fsprogs</code> package as front-ends to various filesystem dependent programs (<code class="literal">mkfs.fstype</code> and <code class="literal">fsck.fstype</code>). For <a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">ext4</a> filesystem, they are <span class="citerefentry"><span class="refentrytitle">mkfs.ext4</span>(8)</span> and <span class="citerefentry"><span class="refentrytitle">fsck.ext4</span>(8)</span> (they are symlinked to <span class="citerefentry"><span class="refentrytitle">mke2fs</span>(8)</span> and <span class="citerefentry"><span class="refentrytitle">e2fsck</span>(8)</span>).</p>
          <p>Similar commands are available for each filesystem supported by Linux.</p>
          <div class="table">
            <a id="listoffilesystemnagementpackages"/>
            <p class="title">
              <strong>Table 9.19. List of filesystem management packages</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of filesystem management packages" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/e2fsprogs">
                  <code class="literal">e2fsprogs</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=e2fsprogs">V:418, I:999</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/e/e2fsprogs.html">4022</a>
                    </td>
                    <td style="text-align: left">
    utilities for the <a class="ulink" href="http://en.wikipedia.org/wiki/Ext2">ext2</a>/<a class="ulink" href="http://en.wikipedia.org/wiki/Ext3">ext3</a>/<a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">ext4</a> filesystems
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/reiserfsprogs">
                  <code class="literal">reiserfsprogs</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=reiserfsprogs">V:5, I:23</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/r/reiserfsprogs.html">893</a>
                    </td>
                    <td style="text-align: left">
    utilities for the <a class="ulink" href="http://en.wikipedia.org/wiki/Reiserfs">Reiserfs</a> filesystem
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/dosfstools">
                  <code class="literal">dosfstools</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=dosfstools">V:83, I:570</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/dosfstools.html">235</a>
                    </td>
                    <td style="text-align: left">
    utilities for the <a class="ulink" href="http://en.wikipedia.org/wiki/File_Allocation_Table">FAT</a> filesystem. (Microsoft: MS-DOS, Windows)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/xfsprogs">
                  <code class="literal">xfsprogs</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=xfsprogs">V:18, I:80</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/x/xfsprogs.html">4338</a>
                    </td>
                    <td style="text-align: left">
    utilities for the <a class="ulink" href="http://en.wikipedia.org/wiki/XFS">XFS</a> filesystem. (SGI: IRIX)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/ntfs-3g">
                  <code class="literal">ntfs-3g</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=ntfs-3g">V:170, I:564</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/n/ntfs-3g.html">1340</a>
                    </td>
                    <td style="text-align: left">
    utilities for the <a class="ulink" href="http://en.wikipedia.org/wiki/NTFS">NTFS</a> filesystem. (Microsoft: Windows NT, …)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/jfsutils">
                  <code class="literal">jfsutils</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=jfsutils">V:1, I:13</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/j/jfsutils.html">1533</a>
                    </td>
                    <td style="text-align: left">
    utilities for the <a class="ulink" href="http://en.wikipedia.org/wiki/JFS_(file_system)">JFS</a> filesystem. (IBM: AIX, OS/2)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/reiser4progs">
                  <code class="literal">reiser4progs</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=reiser4progs">V:0, I:5</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/r/reiser4progs.html">1657</a>
                    </td>
                    <td style="text-align: left">
    utilities for the <a class="ulink" href="http://en.wikipedia.org/wiki/Reiser4">Reiser4</a> filesystem
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/hfsprogs">
                  <code class="literal">hfsprogs</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=hfsprogs">V:0, I:9</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/h/hfsprogs.html">303</a>
                    </td>
                    <td style="text-align: left">
    utilities for <a class="ulink" href="http://en.wikipedia.org/wiki/Hierarchical_File_System">HFS</a> and <a class="ulink" href="http://en.wikipedia.org/wiki/HFS_Plus">HFS Plus</a> filesystem. (Apple: Mac OS)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/btrfs-tools">
                  <code class="literal">btrfs-tools</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=btrfs-tools">V:11, I:40</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/b/btrfs-tools.html">26</a>
                    </td>
                    <td style="text-align: left">
    utilities for the <a class="ulink" href="http://en.wikipedia.org/wiki/Btrfs">Btrfs</a> filesystem
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/zerofree">
                  <code class="literal">zerofree</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=zerofree">V:2, I:53</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/z/zerofree.html">25</a>
                    </td>
                    <td style="text-align: left">
    program to zero free blocks from ext2/3/4 filesystems
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p><a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">Ext4</a> filesystem is the default filesystem for the Linux system and strongly recommended to use it unless you have some specific reasons not to.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p><a class="ulink" href="http://en.wikipedia.org/wiki/Btrfs">Btrfs</a> filesystem is available in Linux kernel 3.2 (Debian <code class="literal">wheezy</code>).  It is expected to be the next default filesystem after the ext4 filesystem.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Warning">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Warning]" src="images/warning.png"/>
                </td>
                <th align="left">Warning</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You should not use the Btrfs filesystem for your critical data yet before it acquires the live kernel space <span class="citerefentry"><span class="refentrytitle">fsck</span>(8)</span> feature and the boot loader support.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Some tools allow access to filesystem without Linux kernel support (see <a class="xref" href="ch09.en.html#_manipulating_files_without_mounting_disk" title="9.7.2. Manipulating files without mounting disk">Section 9.7.2, “Manipulating files without mounting disk”</a>).</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_filesystem_creation_and_integrity_check"/>9.5.6. Filesystem creation and integrity check</h3>
              </div>
            </div>
          </div>
          <p>The <span class="citerefentry"><span class="refentrytitle">mkfs</span>(8)</span> command creates the filesystem on a Linux system. The <span class="citerefentry"><span class="refentrytitle">fsck</span>(8)</span> command provides the filesystem integrity check and repair on a Linux system.</p>
          <p>Debian now defaults to no periodic <code class="literal">fsck</code> after filesystem creation.</p>
          <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Caution">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Caution]" src="images/caution.png"/>
                </td>
                <th align="left">Caution</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>It is generally not safe to run <code class="literal">fsck</code> on <span class="strong"><strong>mounted filesystems</strong></span>.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You can run the <span class="citerefentry"><span class="refentrytitle">fsck</span>(8)</span> command safely on all filesystems including root filesystem on reboot by setting "<code class="literal">enable_periodic_fsck</code>" in "<code class="literal">/etc/mke2fs.conf</code>"  and the max mount count to 0 using "<code class="literal">tune2fs -c0 /dev/&lt;partition_name&gt;</code>".  See <span class="citerefentry"><span class="refentrytitle">mke2fs.conf</span>(5)</span> and <span class="citerefentry"><span class="refentrytitle">tune2fs</span>(8)</span>.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Check files in "<code class="literal">/var/log/fsck/</code>" for the result of the <span class="citerefentry"><span class="refentrytitle">fsck</span>(8)</span> command run from the boot script.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_optimization_of_filesystem_by_mount_options"/>9.5.7. Optimization of filesystem by mount options</h3>
              </div>
            </div>
          </div>
          <p>The basic static filesystem configuration is given by "<code class="literal">/etc/fstab</code>".  For example,</p>
          <pre class="screen"># &lt;file system&gt; &lt;mount point&gt;   &lt;type&gt;  &lt;options&gt;       &lt;dump&gt;  &lt;pass&gt;
proc            /proc           proc    defaults        0       0
UUID=709cbe4c-80c1-56db-8ab1-dbce3146d2f7 / ext4 noatime,errors=remount-ro 0 1
UUID=817bae6b-45d2-5aca-4d2a-1267ab46ac23 none swap sw  0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto 0       0</pre>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p><a class="ulink" href="http://en.wikipedia.org/wiki/Universally_Unique_Identifier">UUID</a> (see <a class="xref" href="ch09.en.html#_accessing_partition_using_uuid" title="9.5.3. Accessing partition using UUID">Section 9.5.3, “Accessing partition using UUID”</a>) may be used to identify a block device instead of normal block device names such as "<code class="literal">/dev/sda1</code>", "<code class="literal">/dev/sda2</code>", …</p>
                </td>
              </tr>
            </table>
          </div>
          <p>Performance and characteristics of a filesystem can be optimized by mount options used on it (see <span class="citerefentry"><span class="refentrytitle">fstab</span>(5)</span> and <span class="citerefentry"><span class="refentrytitle">mount</span>(8)</span>).  Notable ones are the following.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
"<code class="literal">defaults</code>" option implies default options: "<code class="literal">rw,suid,dev,exec,auto,nouser,async</code>". (general)
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">noatime</code>" or "<code class="literal">relatime</code>" option is very effective for speeding up the read access. (general)
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">user</code>" option allows an ordinary user to mount the filesystem. This option implies "<code class="literal">noexec,nosuid,nodev</code>" option combination. (general, used for CDs or usb storage devices)
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">noexec,nodev,nosuid</code>" option combination is used to enhance security. (general)
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">noauto</code>" option limits mounting by explicit operation only. (general)
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">data=journal</code>" option for ext3fs can enhance data integrity against power failure with some loss of write speed.
</p>
              </li>
            </ul>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You need to provide kernel boot parameter (see <a class="xref" href="ch03.en.html#_stage_2_the_boot_loader" title="3.1.2. Stage 2: the boot loader">Section 3.1.2, “Stage 2: the boot loader”</a>), e.g. "<code class="literal">rootflags=data=journal</code>" to deploy a non-default journaling mode for the root filesystem.  For <code class="literal">lenny</code>, the default jounaling mode is "<code class="literal">rootflags=data=ordered</code>".  For <code class="literal">squeeze</code>, it is "<code class="literal">rootflags=data=writeback</code>".</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_optimization_of_filesystem_via_superblock"/>9.5.8. Optimization of filesystem via superblock</h3>
              </div>
            </div>
          </div>
          <p>Characteristics of a filesystem can be optimized via its superblock using the <span class="citerefentry"><span class="refentrytitle">tune2fs</span>(8)</span> command.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
Execution of "<code class="literal">sudo tune2fs -l /dev/hda1</code>" displays the contents of the filesystem superblock on "<code class="literal">/dev/hda1</code>".
</p>
              </li>
              <li class="listitem">
                <p>
Execution of "<code class="literal">sudo tune2fs -c 50 /dev/hda1</code>" changes frequency of filesystem checks (<code class="literal">fsck</code> execution during boot-up) to every 50 boots on "<code class="literal">/dev/hda1</code>".
</p>
              </li>
              <li class="listitem">
                <p>
Execution of "<code class="literal">sudo tune2fs -j /dev/hda1</code>" adds journaling capability to the filesystem, i.e. filesystem conversion from <a class="ulink" href="http://en.wikipedia.org/wiki/Ext2">ext2</a> to <a class="ulink" href="http://en.wikipedia.org/wiki/Ext3">ext3</a> on "<code class="literal">/dev/hda1</code>".  (Do this on the unmounted filesystem.)
</p>
              </li>
              <li class="listitem">
                <p>
Execution of "<code class="literal">sudo tune2fs -O extents,uninit_bg,dir_index /dev/hda1 &amp;&amp; fsck -pf /dev/hda1</code>" converts it from <a class="ulink" href="http://en.wikipedia.org/wiki/Ext3">ext3</a> to <a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">ext4</a> on "<code class="literal">/dev/hda1</code>".  (Do this on the unmounted filesystem.)
</p>
              </li>
            </ul>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Despite its name, <span class="citerefentry"><span class="refentrytitle">tune2fs</span>(8)</span> works not only on the <a class="ulink" href="http://en.wikipedia.org/wiki/Ext2">ext2</a> filesystem but also on the <a class="ulink" href="http://en.wikipedia.org/wiki/Ext3">ext3</a> and <a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">ext4</a> filesystems.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_optimization_of_hard_disk"/>9.5.9. Optimization of hard disk</h3>
              </div>
            </div>
          </div>
          <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Warning">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Warning]" src="images/warning.png"/>
                </td>
                <th align="left">Warning</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Please check your hardware and read manpage of <span class="citerefentry"><span class="refentrytitle">hdparam</span>(8)</span> before playing with hard disk configuration because this may be quite dangerous for the data integrity.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>You can test disk access speed of a hard disk, e.g. "<code class="literal">/dev/hda</code>", by "<code class="literal">hdparm -tT /dev/hda</code>". For some hard disk connected with (E)IDE, you can speed it up with "<code class="literal">hdparm -q -c3 -d1 -u1 -m16 /dev/hda</code>" by enabling the "(E)IDE 32-bit I/O support", enabling the "using_dma flag", setting "interrupt-unmask flag", and setting the "multiple 16 sector I/O" (dangerous!).</p>
          <p>You can test write cache feature of a hard disk, e.g. "<code class="literal">/dev/sda</code>", by "<code class="literal">hdparm -W /dev/sda</code>". You can disable its write cache feature with "<code class="literal">hdparm -W 0 /dev/sda</code>".</p>
          <p>You may be able to read badly pressed CDROMs on modern high speed CD-ROM drive by slowing it down with "<code class="literal">setcd -x 2</code>".</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_optimization_of_solid_state_drive"/>9.5.10. Optimization of solid state drive</h3>
              </div>
            </div>
          </div>
          <p>Performance and disk wear of the <a class="ulink" href="http://en.wikipedia.org/wiki/Solid-state_drive">solid state drive (SSD)</a> can be optimized as follows.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
Use the latest Linux kernel. (&gt;= 3.2)
</p>
              </li>
              <li class="listitem">
                <p>
Reduce disk writes for read disk accesses.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
Set "<code class="literal">noatime</code>" or "<code class="literal">relatime</code>" mount option in <code class="literal">/etc/fstab</code>.
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Enable the <a class="ulink" href="http://en.wikipedia.org/wiki/TRIM">TRIM</a> command.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
Set "<code class="literal">discard</code>" mount option in <code class="literal">/etc/fstab</code> for the ext4 filesystem, swap partition, Btrfs, etc. See <span class="citerefentry"><span class="refentrytitle">fstab</span>(5)</span>.
</p>
                    </li>
                    <li class="listitem">
                      <p>
Set "<code class="literal">discard</code>" option in <code class="literal">/etc/lvm/lvm.conf</code> for <a class="ulink" href="http://en.wikipedia.org/wiki/Logical_Volume_Manager_(Linux)">LVM</a>. See <span class="citerefentry"><span class="refentrytitle">lvm.conf</span>(5)</span>.
</p>
                    </li>
                    <li class="listitem">
                      <p>
Set "<code class="literal">discard</code>" option in <code class="literal">/etc/crypttab</code> for <a class="ulink" href="http://en.wikipedia.org/wiki/Dm-crypt">dm-crypt</a>. See <span class="citerefentry"><span class="refentrytitle">crypttab</span>(5)</span>.
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Enable the SSD optimized disk space allocation scheme.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
Set "<code class="literal">ssd</code>" mount option in <code class="literal">/etc/fstab</code> for the Btrfs.
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Make system flush data to the disk every 10 minutes for laptop PCs.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
Set "<code class="literal">commit=600</code>" mount option in <code class="literal">/etc/fstab</code>. See <span class="citerefentry"><span class="refentrytitle">fstab</span>(5)</span>.
</p>
                    </li>
                    <li class="listitem">
                      <p>
Set pm-utils to use laptop-mode even under AC operation. See <a class="ulink" href="http://bugs.debian.org/659260">Debian BTS #659260</a>.
</p>
                    </li>
                  </ul>
                </div>
              </li>
            </ul>
          </div>
          <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Warning">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Warning]" src="images/warning.png"/>
                </td>
                <th align="left">Warning</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Changing flushing interval from normal 5 seconds to 10 minutes makes your data vulnerable to the power failure.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_using_smart_to_predict_hard_disk_failure"/>9.5.11. Using SMART to predict hard disk failure</h3>
              </div>
            </div>
          </div>
          <p>You can monitor and log your hard disk which is compliant to <a class="ulink" href="http://en.wikipedia.org/wiki/S.M.A.R.T.">SMART</a> with the <span class="citerefentry"><span class="refentrytitle">smartd</span>(8)</span> daemon.</p>
          <div class="orderedlist">
            <ol class="orderedlist">
              <li class="listitem">
                <p>
Enable <a class="ulink" href="http://en.wikipedia.org/wiki/S.M.A.R.T.">SMART</a> feature in <a class="ulink" href="http://en.wikipedia.org/wiki/BIOS">BIOS</a>.
</p>
              </li>
              <li class="listitem">
                <p>
Install the <code class="literal">smartmontools</code> package.
</p>
              </li>
              <li class="listitem">
                <p>
Identify your hard disk drives by listing them with <span class="citerefentry"><span class="refentrytitle">df</span>(1)</span>.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
Let's assume a hard disk drive to be monitored as "<code class="literal">/dev/hda</code>".
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Check the output of "<code class="literal">smartctl -a /dev/hda</code>" to see if <a class="ulink" href="http://en.wikipedia.org/wiki/S.M.A.R.T.">SMART</a> feature is actually enabled.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
If not, enable it by "<code class="literal">smartctl -s on -a /dev/hda</code>".
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Enable <span class="citerefentry"><span class="refentrytitle">smartd</span>(8)</span> daemon to run by the following.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
uncomment "<code class="literal">start_smartd=yes</code>" in the "<code class="literal">/etc/default/smartmontools</code>" file.
</p>
                    </li>
                    <li class="listitem">
                      <p>
restart the <span class="citerefentry"><span class="refentrytitle">smartd</span>(8)</span> daemon by "<code class="literal">sudo /etc/init.d/smartmontools restart</code>".
</p>
                    </li>
                  </ul>
                </div>
              </li>
            </ol>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>The <span class="citerefentry"><span class="refentrytitle">smartd</span>(8)</span> daemon can be customized with the <code class="literal">/etc/smartd.conf</code> file including how to be notified of warnings.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_specify_temporary_storage_directory_via_tmpdir"/>9.5.12. Specify temporary storage directory via $TMPDIR</h3>
              </div>
            </div>
          </div>
          <p>Applications create temporary files normally under the temporary storage directory "<code class="literal">/tmp</code>".  If "<code class="literal">/tmp</code>" does not provide enough space, you can specify such temporary storage directory via the <code class="literal">$TMPDIR</code> variable for well-behaving programs.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_expansion_of_usable_storage_space_via_lvm"/>9.5.13. Expansion of usable storage space via LVM</h3>
              </div>
            </div>
          </div>
          <p>For partitions created on <a class="ulink" href="http://en.wikipedia.org/wiki/Logical_Volume_Manager_(Linux)">Logical Volume Manager (LVM)</a> (Linux feature) at install time, they can be resized easily by concatenating extents onto them or truncating extents from them over multiple storage devices without major system reconfiguration.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_expansion_of_usable_storage_space_by_mounting_another_partition"/>9.5.14. Expansion of usable storage space by mounting another partition</h3>
              </div>
            </div>
          </div>
          <p>If you have an empty partition (e.g., "<code class="literal">/dev/sdx</code>"), you can format it with <span class="citerefentry"><span class="refentrytitle">mkfs.ext4</span>(1)</span> and <span class="citerefentry"><span class="refentrytitle">mount</span>(8)</span> it to a directory where you need more space. (You need to copy original data contents.)</p>
          <pre class="screen">$ sudo mv work-dir old-dir
$ sudo mkfs.ext4 /dev/sdx
$ sudo mount -t ext4 /dev/sdx work-dir
$ sudo cp -a old-dir/* work-dir
$ sudo rm -rf old-dir</pre>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You may alternatively mount an empty disk image file (see <a class="xref" href="ch09.en.html#_making_the_empty_disk_image_file" title="9.6.5. Making the empty disk image file">Section 9.6.5, “Making the empty disk image file”</a>) as a loop device (see <a class="xref" href="ch09.en.html#_mounting_the_disk_image_file" title="9.6.3. Mounting the disk image file">Section 9.6.3, “Mounting the disk image file”</a>).  The actual disk usage grows with the actual data stored.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_expansion_of_usable_storage_space_by_bind_mounting_another_directory"/>9.5.15. Expansion of usable storage space by bind-mounting another directory</h3>
              </div>
            </div>
          </div>
          <p>If you have an empty directory (e.g., "<code class="literal">/path/to/emp-dir</code>") on another partition with usable space, you can mount(8) it with "<code class="literal">--bind</code>" option to a directory (e.g., "<code class="literal">work-dir</code>") where you need more space.</p>
          <pre class="screen">$ sudo mount --bind /path/to/emp-dir work-dir</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_expansion_of_usable_storage_space_using_symlink"/>9.5.16. Expansion of usable storage space using symlink</h3>
              </div>
            </div>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>This is a deprecated method.  Use <a class="xref" href="ch09.en.html#_expansion_of_usable_storage_space_by_bind_mounting_another_directory" title="9.5.15. Expansion of usable storage space by bind-mounting another directory">Section 9.5.15, “Expansion of usable storage space by bind-mounting another directory”</a> instead, if possible.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>If you have an empty directory (e.g., "<code class="literal">/path/to/emp-dir</code>") in another partition with usable space, you can create a symlink to the directory with <span class="citerefentry"><span class="refentrytitle">ln</span>(8)</span>.</p>
          <pre class="screen">$ sudo mv work-dir old-dir
$ sudo mkdir -p /path/to/emp-dir
$ sudo ln -sf /path/to/emp-dir work-dir
$ sudo cp -a old-dir/* work-dir
$ sudo rm -rf old-dir</pre>
          <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Warning">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Warning]" src="images/warning.png"/>
                </td>
                <th align="left">Warning</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Do not use "symlink to a directory" for directories managed by the system such as "<code class="literal">/opt</code>".  Such a symlink may be overwritten when the system is upgraded.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Caution">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Caution]" src="images/caution.png"/>
                </td>
                <th align="left">Caution</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Some software may not function well with "symlink to a directory".</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_expansion_of_usable_storage_space_using_overlayfs"/>9.5.17. Expansion of usable storage space using overlayfs</h3>
              </div>
            </div>
          </div>
          <p>If you have usable space in another partition (e.g., "<code class="literal">/path/to/empty</code>" and "<code class="literal">/path/to/work</code>"), you can create a directory in it and stack that on to an old directory (e.g., "<code class="literal">/path/to/old</code>") where you need space with <a class="ulink" href="https://en.wikipedia.org/wiki/OverlayFS">OverlayFS</a> with Linux kernel 3.18 or newer (Debian Stetch 9.0 or newer).</p>
          <pre class="screen">$ sudo mount -t overlay overlay \
  -olowerdir=/path/to/old-dir,upperdir=/path/to/empty,workdir=/path/to/work</pre>
          <p>Here, "<code class="literal">/path/to/empty</code>" and "<code class="literal">/path/to/work</code>" should be on the RW-enabled partition to write on "<code class="literal">/path/to/old</code>".</p>
        </div>
      </div>
      <div class="section">
        <div class="titlepage">
          <div>
            <div>
              <h2 class="title"><a id="_the_disk_image"/>9.6. The disk image</h2>
            </div>
          </div>
        </div>
        <p>Here, we discuss manipulations of the disk image.</p>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_making_the_disk_image_file"/>9.6.1. Making the disk image file</h3>
              </div>
            </div>
          </div>
          <p>The disk image file, "<code class="literal">disk.img</code>", of an unmounted device, e.g., the second SCSI or serial ATA drive "<code class="literal">/dev/sdb</code>", can be made using <span class="citerefentry"><span class="refentrytitle">cp</span>(1)</span> or <span class="citerefentry"><span class="refentrytitle">dd</span>(1)</span> by the following.</p>
          <pre class="screen"># cp /dev/sdb disk.img
# dd if=/dev/sdb of=disk.img</pre>
          <p>The disk image of the traditional PC's <a class="ulink" href="http://en.wikipedia.org/wiki/Master_boot_record">master boot record (MBR)</a> (see <a class="xref" href="ch09.en.html#_disk_partition_configuration" title="9.5.2. Disk partition configuration">Section 9.5.2, “Disk partition configuration”</a>) which reside on the first sector on the primary IDE disk can be made by using <span class="citerefentry"><span class="refentrytitle">dd</span>(1)</span> by the following.</p>
          <pre class="screen"># dd if=/dev/hda of=mbr.img bs=512 count=1
# dd if=/dev/hda of=mbr-nopart.img bs=446 count=1
# dd if=/dev/hda of=mbr-part.img skip=446 bs=1 count=66</pre>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
"<code class="literal">mbr.img</code>": The MBR with the partition table
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">mbr-nopart.img</code>": The MBR without the partition table
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">mbr-part.img</code>": The partition table of the MBR only
</p>
              </li>
            </ul>
          </div>
          <p>If you have an SCSI or serial ATA device as the boot disk, substitute "<code class="literal">/dev/hda</code>" with "<code class="literal">/dev/sda</code>".</p>
          <p>If you are making an image of a disk partition of the original disk, substitute "<code class="literal">/dev/hda</code>" with "<code class="literal">/dev/hda1</code>" etc.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_writing_directly_to_the_disk"/>9.6.2. Writing directly to the disk</h3>
              </div>
            </div>
          </div>
          <p>The disk image file, "<code class="literal">disk.img</code>" can be written to an unmounted device, e.g., the second SCSI drive "<code class="literal">/dev/sdb</code>" with matching size, by the following.</p>
          <pre class="screen"># dd if=disk.img of=/dev/sdb</pre>
          <p>Similarly, the disk partition image file, "<code class="literal">partition.img</code>" can be written to an unmounted partition, e.g., the first partition of the second SCSI drive "<code class="literal">/dev/sdb1</code>" with matching size, by the following.</p>
          <pre class="screen"># dd if=partition.img of=/dev/sdb1</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_mounting_the_disk_image_file"/>9.6.3. Mounting the disk image file</h3>
              </div>
            </div>
          </div>
          <p>The disk image "<code class="literal">partition.img</code>" containing a single partition image can be mounted and unmounted by using the <a class="ulink" href="http://en.wikipedia.org/wiki/Loop_device">loop device</a> as follows.</p>
          <pre class="screen"># losetup -v -f partition.img
Loop device is /dev/loop0
# mkdir -p /mnt/loop0
# mount -t auto /dev/loop0 /mnt/loop0
...hack...hack...hack
# umount /dev/loop0
# losetup -d /dev/loop0</pre>
          <p>This can be simplified as follows.</p>
          <pre class="screen"># mkdir -p /mnt/loop0
# mount -t auto -o loop partition.img /mnt/loop0
...hack...hack...hack
# umount partition.img</pre>
          <p>Each partition of the disk image "<code class="literal">disk.img</code>" containing multiple partitions can be mounted by using the <a class="ulink" href="http://en.wikipedia.org/wiki/Loop_device">loop device</a>.  Since the loop device does not manage partitions by default, we need to reset it as follows.</p>
          <pre class="screen"># modinfo -p loop # verify kernel capability
max_part:Maximum number of partitions per loop device
max_loop:Maximum number of loop devices
# losetup -a # verify nothing using the loop device
# rmmod loop
# modprobe loop max_part=16</pre>
          <p>Now, the loop device can manage up to 16 partitions.</p>
          <pre class="screen"># losetup -v -f disk.img
Loop device is /dev/loop0
# fdisk -l /dev/loop0

Disk /dev/loop0: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x452b6464

      Device Boot      Start         End      Blocks   Id  System
/dev/loop0p1               1         600     4819468+  83  Linux
/dev/loop0p2             601         652      417690   83  Linux
# mkdir -p /mnt/loop0p1
# mount -t ext4 /dev/loop0p1 /mnt/loop0p1
# mkdir -p /mnt/loop0p2
# mount -t ext4 /dev/loop0p2 /mnt/loop0p2
...hack...hack...hack
# umount /dev/loop0p1
# umount /dev/loop0p2
# losetup -d /dev/loop0</pre>
          <p>Alternatively, similar effects can be done by using the <a class="ulink" href="http://en.wikipedia.org/wiki/Device_mapper">device mapper</a> devices created by <span class="citerefentry"><span class="refentrytitle">kpartx</span>(8)</span> from the <code class="literal">kpartx</code> package as follows.</p>
          <pre class="screen"># kpartx -a -v disk.img
...
# mkdir -p /mnt/loop0p2
# mount -t ext4 /dev/mapper/loop0p2 /mnt/loop0p2
...
...hack...hack...hack
# umount /dev/mapper/loop0p2
...
# kpartx -d /mnt/loop0</pre>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You can mount a single partition of such disk image with <a class="ulink" href="http://en.wikipedia.org/wiki/Loop_device">loop device</a> using offset to skip <a class="ulink" href="http://en.wikipedia.org/wiki/Master_boot_record">MBR</a> etc., too.  But this is more error prone.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_cleaning_a_disk_image_file"/>9.6.4. Cleaning a disk image file</h3>
              </div>
            </div>
          </div>
          <p>A disk image file, "<code class="literal">disk.img</code>" can be cleaned of all removed files into clean sparse image "<code class="literal">new.img</code>" by the following.</p>
          <pre class="screen"># mkdir old; mkdir new
# mount -t auto -o loop disk.img old
# dd bs=1 count=0 if=/dev/zero of=new.img seek=5G
# mount -t auto -o loop new.img new
# cd old
# cp -a --sparse=always ./ ../new/
# cd ..
# umount new.img
# umount disk.img</pre>
          <p>If "<code class="literal">disk.img</code>" is in ext2, ext3 or ext4, you can also use <span class="citerefentry"><span class="refentrytitle">zerofree</span>(8)</span> from the <code class="literal">zerofree</code> package as follows.</p>
          <pre class="screen"># losetup -f -v disk.img
Loop device is /dev/loop3
# zerofree /dev/loop3
# cp --sparse=always disk.img new.img</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_making_the_empty_disk_image_file"/>9.6.5. Making the empty disk image file</h3>
              </div>
            </div>
          </div>
          <p>The empty disk image "<code class="literal">disk.img</code>" which can grow up to 5GiB can be made using <span class="citerefentry"><span class="refentrytitle">dd</span>(1)</span> as follows.</p>
          <pre class="screen">$ dd bs=1 count=0 if=/dev/zero of=disk.img seek=5G</pre>
          <p>You can create an ext4 filesystem on this disk image "<code class="literal">disk.img</code>" using the <a class="ulink" href="http://en.wikipedia.org/wiki/Loop_device">loop device</a> as follows.</p>
          <pre class="screen"># losetup -f -v disk.img
Loop device is /dev/loop1
# mkfs.ext4 /dev/loop1
...hack...hack...hack
# losetup -d /dev/loop1
$ du  --apparent-size -h disk.img
5.0G  disk.img
$ du -h disk.img
83M disk.img</pre>
          <p>For "<code class="literal">disk.img</code>", its file size is 5.0 GiB and its actual disk usage is mere 83MiB.  This discrepancy is possible since <a class="ulink" href="http://en.wikipedia.org/wiki/Ext4">ext4</a> can hold <a class="ulink" href="http://en.wikipedia.org/wiki/Sparse_file">sparse file</a>.</p>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>The actual disk usage of <a class="ulink" href="http://en.wikipedia.org/wiki/Sparse_file">sparse file</a> grows with data which are written to it.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>Using similar operation on devices created by the <a class="ulink" href="http://en.wikipedia.org/wiki/Loop_device">loop device</a> or the <a class="ulink" href="http://en.wikipedia.org/wiki/Device_mapper">device mapper</a> devices as  <a class="xref" href="ch09.en.html#_mounting_the_disk_image_file" title="9.6.3. Mounting the disk image file">Section 9.6.3, “Mounting the disk image file”</a>, you can partition this disk image "<code class="literal">disk.img</code>" using <span class="citerefentry"><span class="refentrytitle">parted</span>(8)</span> or <span class="citerefentry"><span class="refentrytitle">fdisk</span>(8)</span>, and can create filesystem on it using <span class="citerefentry"><span class="refentrytitle">mkfs.ext4</span>(8)</span>, <span class="citerefentry"><span class="refentrytitle">mkswap</span>(8)</span>, etc.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_making_the_iso9660_image_file"/>9.6.6. Making the ISO9660 image file</h3>
              </div>
            </div>
          </div>
          <p>The <a class="ulink" href="http://en.wikipedia.org/wiki/ISO_9660">ISO9660</a> image file, "<code class="literal">cd.iso</code>", from the source directory tree at "<code class="literal">source_directory</code>" can be made using <span class="citerefentry"><span class="refentrytitle">genisoimage</span>(1)</span> provided by <a class="ulink" href="http://en.wikipedia.org/wiki/Cdrkit">cdrkit</a> by the following.</p>
          <pre class="screen">#  genisoimage -r -J -T -V volume_id -o cd.iso source_directory</pre>
          <p>Similarly, the bootable ISO9660 image file, "<code class="literal">cdboot.iso</code>", can be made from <code class="literal">debian-installer</code> like directory tree at "<code class="literal">source_directory</code>" by the following.</p>
          <pre class="screen">#  genisoimage -r -o cdboot.iso -V volume_id \
   -b isolinux/isolinux.bin -c isolinux/boot.cat \
   -no-emul-boot -boot-load-size 4 -boot-info-table source_directory</pre>
          <p>Here <a class="ulink" href="http://en.wikipedia.org/wiki/SYSLINUX">Isolinux boot loader</a> (see <a class="xref" href="ch03.en.html#_stage_2_the_boot_loader" title="3.1.2. Stage 2: the boot loader">Section 3.1.2, “Stage 2: the boot loader”</a>) is used for booting.</p>
          <p>You can calculate the md5sum value and make the ISO9660 image directly from the CD-ROM device as follows.</p>
          <pre class="screen">$ isoinfo -d -i /dev/cdrom
CD-ROM is in ISO 9660 format
...
Logical block size is: 2048
Volume size is: 23150592
...
# dd if=/dev/cdrom bs=2048 count=23150592 conv=notrunc,noerror | md5sum
# dd if=/dev/cdrom bs=2048 count=23150592 conv=notrunc,noerror &gt; cd.iso</pre>
          <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Warning">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Warning]" src="images/warning.png"/>
                </td>
                <th align="left">Warning</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You must carefully avoid ISO9660 filesystem read ahead bug of Linux as above to get the right result.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_writing_directly_to_the_cd_dvd_r_rw"/>9.6.7. Writing directly to the CD/DVD-R/RW</h3>
              </div>
            </div>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>DVD is only a large CD to <span class="citerefentry"><span class="refentrytitle">wodim</span>(1)</span> provided by <a class="ulink" href="http://en.wikipedia.org/wiki/Cdrkit">cdrkit</a>.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>You can find a usable device by the following.</p>
          <pre class="screen"># wodim --devices</pre>
          <p>Then the blank CD-R is inserted to the CD drive, and the ISO9660 image file, "<code class="literal">cd.iso</code>" is written to this device, e.g., "<code class="literal">/dev/hda</code>", using <span class="citerefentry"><span class="refentrytitle">wodim</span>(1)</span> by the following.</p>
          <pre class="screen"># wodim -v -eject dev=/dev/hda cd.iso</pre>
          <p>If CD-RW is used instead of CD-R, do this instead by the following.</p>
          <pre class="screen"># wodim -v -eject blank=fast dev=/dev/hda cd.iso</pre>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>If your desktop system mounts CDs automatically, unmount it by "<code class="literal">sudo umount /dev/hda</code>" from console before using <span class="citerefentry"><span class="refentrytitle">wodim</span>(1)</span>.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_mounting_the_iso9660_image_file"/>9.6.8. Mounting the ISO9660 image file</h3>
              </div>
            </div>
          </div>
          <p>If "<code class="literal">cd.iso</code>" contains an ISO9660 image, then the following manually mounts it to "<code class="literal">/cdrom</code>".</p>
          <pre class="screen"># mount -t iso9660 -o ro,loop cd.iso /cdrom</pre>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Modern desktop system may mount removable media such as ISO9660 formatted CD automatically (see <a class="xref" href="ch10.en.html#_removable_storage_device" title="10.1.7. Removable storage device">Section 10.1.7, “Removable storage device”</a>).</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
      </div>
      <div class="section">
        <div class="titlepage">
          <div>
            <div>
              <h2 class="title"><a id="_the_binary_data"/>9.7. The binary data</h2>
            </div>
          </div>
        </div>
        <p>Here, we discuss direct manipulations of the binary data on storage media.</p>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_viewing_and_editing_binary_data"/>9.7.1. Viewing and editing binary data</h3>
              </div>
            </div>
          </div>
          <p>The most basic viewing method of binary data is to use "<code class="literal">od -t x1</code>" command.</p>
          <div class="table">
            <a id="listofpackageswhndeditbinarydata"/>
            <p class="title">
              <strong>Table 9.20. List of packages which view and edit binary data</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of packages which view and edit binary data" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/coreutils">
                  <code class="literal">coreutils</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=coreutils">V:881, I:999</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/c/coreutils.html">15103</a>
                    </td>
                    <td style="text-align: left">
    basic package which has <span class="citerefentry"><span class="refentrytitle">od</span>(1)</span> to dump files (HEX, ASCII, OCTAL, …)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/bsdmainutils">
                  <code class="literal">bsdmainutils</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=bsdmainutils">V:866, I:998</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/b/bsdmainutils.html">566</a>
                    </td>
                    <td style="text-align: left">
    utility package which has <span class="citerefentry"><span class="refentrytitle">hd</span>(1)</span> to dump files (HEX, ASCII, OCTAL, …)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/hexedit">
                  <code class="literal">hexedit</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=hexedit">V:1, I:11</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/h/hexedit.html">61</a>
                    </td>
                    <td style="text-align: left">
    binary editor and viewer (HEX, ASCII)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/bless">
                  <code class="literal">bless</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=bless">V:0, I:5</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/b/bless.html">973</a>
                    </td>
                    <td style="text-align: left">
    full featured hexadecimal editor (GNOME)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/okteta">
                  <code class="literal">okteta</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=okteta">V:2, I:22</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/o/okteta.html">382</a>
                    </td>
                    <td style="text-align: left">
    full featured hexadecimal editor (KDE4)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/ncurses-hexedit">
                  <code class="literal">ncurses-hexedit</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=ncurses-hexedit">V:0, I:2</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/n/ncurses-hexedit.html">126</a>
                    </td>
                    <td style="text-align: left">
    binary editor and viewer (HEX, ASCII, EBCDIC)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/beav">
                  <code class="literal">beav</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=beav">V:0, I:1</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/b/beav.html">133</a>
                    </td>
                    <td style="text-align: left">
    binary editor and viewer (HEX, ASCII, EBCDIC, OCTAL, …)
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>HEX is used as an acronym for <a class="ulink" href="http://en.wikipedia.org/wiki/Hexadecimal">hexadecimal</a> format with <a class="ulink" href="http://en.wikipedia.org/wiki/Radix">radix</a> 16.  OCTAL is for <a class="ulink" href="http://en.wikipedia.org/wiki/Octal">octal</a> format with <a class="ulink" href="http://en.wikipedia.org/wiki/Radix">radix</a> 8.  ASCII is for <a class="ulink" href="http://en.wikipedia.org/wiki/ASCII">American Standard Code for Information Interchange</a>, i.e., normal English text code.  EBCDIC is for <a class="ulink" href="http://en.wikipedia.org/wiki/Extended_Binary_Coded_Decimal_Interchange_Code">Extended Binary Coded Decimal Interchange Code</a> used on <a class="ulink" href="http://en.wikipedia.org/wiki/IBM_mainframe">IBM mainframe</a> operating systems.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_manipulating_files_without_mounting_disk"/>9.7.2. Manipulating files without mounting disk</h3>
              </div>
            </div>
          </div>
          <p>There are tools to read and write files without mounting disk.</p>
          <div class="table">
            <a id="listofpackagestohoutmountingdisk"/>
            <p class="title">
              <strong>Table 9.21. List of packages to manipulate files without mounting disk</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of packages to manipulate files without mounting disk" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/mtools">
                  <code class="literal">mtools</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=mtools">V:13, I:114</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/m/mtools.html">361</a>
                    </td>
                    <td style="text-align: left">
    utilities for MSDOS files without mounting them
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/hfsutils">
                  <code class="literal">hfsutils</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=hfsutils">V:0, I:9</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/h/hfsutils.html">1842</a>
                    </td>
                    <td style="text-align: left">
    utilities for HFS and HFS+ files without mounting them
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_data_redundancy"/>9.7.3. Data redundancy</h3>
              </div>
            </div>
          </div>
          <p>Software <a class="ulink" href="http://en.wikipedia.org/wiki/RAID">RAID</a> systems offered by the Linux kernel provide data redundancy in the kernel filesystem level to achieve high levels of storage reliability.</p>
          <p>There are tools to add data redundancy to files in application program level to achieve high levels of storage reliability, too.</p>
          <div class="table">
            <a id="listoftoolstoaddedundancytofiles"/>
            <p class="title">
              <strong>Table 9.22. List of tools to add data redundancy to files</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of tools to add data redundancy to files" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/par2">
                  <code class="literal">par2</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=par2">V:2, I:11</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/p/par2.html">238</a>
                    </td>
                    <td style="text-align: left">
    Parity Archive Volume Set, for checking and repair of files
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/dvdisaster">
                  <code class="literal">dvdisaster</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=dvdisaster">V:0, I:2</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/dvdisaster.html">1743</a>
                    </td>
                    <td style="text-align: left">
    data loss/scratch/aging protection for CD/DVD media
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/dvbackup">
                  <code class="literal">dvbackup</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=dvbackup">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/dvbackup.html">412</a>
                    </td>
                    <td style="text-align: left">
    backup tool using MiniDV camcorders (providing <span class="citerefentry"><span class="refentrytitle">rsbep</span>(1)</span>)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/vdmfec">
                  <code class="literal">vdmfec</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=vdmfec">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/v/vdmfec.html">97</a>
                    </td>
                    <td style="text-align: left">
    recover lost blocks using Forward Error Correction
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_data_file_recovery_and_forensic_analysis"/>9.7.4. Data file recovery and forensic analysis</h3>
              </div>
            </div>
          </div>
          <p>There are tools for data file recovery and forensic analysis.</p>
          <div class="table">
            <a id="listofpackagesfoforensicanalysis"/>
            <p class="title">
              <strong>Table 9.23. List of packages for data file recovery and forensic analysis</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of packages for data file recovery and forensic analysis" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/testdisk">
                  <code class="literal">testdisk</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=testdisk">V:4, I:39</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/t/testdisk.html">1344</a>
                    </td>
                    <td style="text-align: left">
    utilities for partition scan and disk recovery
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/magicrescue">
                  <code class="literal">magicrescue</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=magicrescue">V:0, I:3</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/m/magicrescue.html">220</a>
                    </td>
                    <td style="text-align: left">
    utility to recover files by looking for magic bytes
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/scalpel">
                  <code class="literal">scalpel</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=scalpel">V:0, I:4</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/scalpel.html">82</a>
                    </td>
                    <td style="text-align: left">
    frugal, high performance file carver
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/myrescue">
                  <code class="literal">myrescue</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=myrescue">V:0, I:2</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/m/myrescue.html">38</a>
                    </td>
                    <td style="text-align: left">
    rescue data from damaged harddisks
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/extundelete">
                  <code class="literal">extundelete</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=extundelete">V:0, I:11</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/e/extundelete.html">148</a>
                    </td>
                    <td style="text-align: left">
    utility to undelete files on the ext3/4 filesystem
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/ext4magic">
                  <code class="literal">ext4magic</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=ext4magic">V:0, I:2</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/e/ext4magic.html">232</a>
                    </td>
                    <td style="text-align: left">
    utility to undelete files on the ext3/4 filesystem
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/ext3grep">
                  <code class="literal">ext3grep</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=ext3grep">V:0, I:3</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/e/ext3grep.html">278</a>
                    </td>
                    <td style="text-align: left">
    tool to help recover deleted files on the ext3 filesystem
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/scrounge-ntfs">
                  <code class="literal">scrounge-ntfs</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=scrounge-ntfs">V:0, I:3</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/scrounge-ntfs.html">45</a>
                    </td>
                    <td style="text-align: left">
    data recovery program for NTFS filesystems
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/gzrt">
                  <code class="literal">gzrt</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=gzrt">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/g/gzrt.html">57</a>
                    </td>
                    <td style="text-align: left">
    gzip recovery toolkit
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/sleuthkit">
                  <code class="literal">sleuthkit</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=sleuthkit">V:1, I:8</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/sleuthkit.html">1114</a>
                    </td>
                    <td style="text-align: left">
    tools for forensics analysis. (Sleuthkit)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/autopsy">
                  <code class="literal">autopsy</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=autopsy">V:0, I:2</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/a/autopsy.html">1021</a>
                    </td>
                    <td style="text-align: left">
    graphical interface to SleuthKit
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/foremost">
                  <code class="literal">foremost</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=foremost">V:0, I:7</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/f/foremost.html">123</a>
                    </td>
                    <td style="text-align: left">
    forensics application to recover data
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/guymager">
                  <code class="literal">guymager</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=guymager">V:0, I:0</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/g/guymager.html">1104</a>
                    </td>
                    <td style="text-align: left">
    forensic imaging tool based on Qt
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/dcfldd">
                  <code class="literal">dcfldd</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=dcfldd">V:0, I:5</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/dcfldd.html">94</a>
                    </td>
                    <td style="text-align: left">
    enhanced version of <code class="literal">dd</code> for forensics and security
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You can undelete files on the ext2 filesystem using <code class="literal">list_deleted_inodes</code> and <code class="literal">undel</code> commands of <span class="citerefentry"><span class="refentrytitle">debugfs</span>(8)</span> in the <code class="literal">e2fsprogs</code> package.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_splitting_a_large_file_into_small_files"/>9.7.5. Splitting a large file into small files</h3>
              </div>
            </div>
          </div>
          <p>When a data is too big to backup as a single file, you can backup its content after splitting it into, e.g. 2000MiB chunks and merge those chunks back into the original file later.</p>
          <pre class="screen">$ split -b 2000m large_file
$ cat x* &gt;large_file</pre>
          <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Caution">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Caution]" src="images/caution.png"/>
                </td>
                <th align="left">Caution</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Please make sure you do not have any files starting with "<code class="literal">x</code>" to avoid name crashes.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_clearing_file_contents"/>9.7.6. Clearing file contents</h3>
              </div>
            </div>
          </div>
          <p>In order to clear the contents of a file such as a log file, do not use <span class="citerefentry"><span class="refentrytitle">rm</span>(1)</span> to delete the file and then create a new empty file, because the file may still be accessed in the interval between commands.  The following is the safe way to clear the contents of the file.</p>
          <pre class="screen">$ :&gt;file_to_be_cleared</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_dummy_files"/>9.7.7. Dummy files</h3>
              </div>
            </div>
          </div>
          <p>The following commands create dummy or empty files.</p>
          <pre class="screen">$ dd if=/dev/zero    of=5kb.file bs=1k count=5
$ dd if=/dev/urandom of=7mb.file bs=1M count=7
$ touch zero.file
$ : &gt; alwayszero.file</pre>
          <p>You should find following files.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
"<code class="literal">5kb.file</code>" is 5KB of zeros.
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">7mb.file</code>" is 7MB of random data.
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">zero.file</code>" may be a 0 byte file.  If it existed, its <code class="literal">mtime</code> is updated while its content and its length are kept.
</p>
              </li>
              <li class="listitem">
                <p>
"<code class="literal">alwayszero.file</code>" is always a 0 byte file.  If it existed, its <code class="literal">mtime</code> is updated and its content is reset.
</p>
              </li>
            </ul>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_erasing_an_entire_hard_disk"/>9.7.8. Erasing an entire hard disk</h3>
              </div>
            </div>
          </div>
          <p>There are several ways to completely erase data from an entire hard disk like device, e.g., USB memory stick at "<code class="literal">/dev/sda</code>".</p>
          <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Caution">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Caution]" src="images/caution.png"/>
                </td>
                <th align="left">Caution</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Check your USB memory stick location with <span class="citerefentry"><span class="refentrytitle">mount</span>(8)</span> first before executing commands here.  The device pointed by "<code class="literal">/dev/sda</code>" may be SCSI hard disk or serial-ATA hard disk where your entire system resides.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>Erase all the disk content by resetting data to 0 with the following.</p>
          <pre class="screen"># dd if=/dev/zero of=/dev/sda</pre>
          <p>Erase everything by overwriting with random data as follows.</p>
          <pre class="screen"># dd if=/dev/urandom of=/dev/sda</pre>
          <p>Erase everything by overwriting with random data very efficiently as follows.</p>
          <pre class="screen"># shred -v -n 1 /dev/sda</pre>
          <p>Since <span class="citerefentry"><span class="refentrytitle">dd</span>(1)</span> is available from the shell of many bootable Linux CDs such as Debian installer CD, you can erase your installed system completely by running an erase command from such media on the system hard disk, e.g., "<code class="literal">/dev/hda</code>", "<code class="literal">/dev/sda</code>", etc.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_erasing_unused_area_of_an_hard_disk"/>9.7.9. Erasing unused area of an hard disk</h3>
              </div>
            </div>
          </div>
          <p>Unused area on an hard disk (or USB memory stick), e.g. "<code class="literal">/dev/sdb1</code>" may still contain erased data themselves since they are only unlinked from the filesystem.  These can be cleaned by overwriting them.</p>
          <pre class="screen"># mount -t auto /dev/sdb1 /mnt/foo
# cd /mnt/foo
# dd if=/dev/zero of=junk
dd: writing to `junk': No space left on device
...
# sync
# umount /dev/sdb1</pre>
          <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Warning">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Warning]" src="images/warning.png"/>
                </td>
                <th align="left">Warning</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>This is usually good enough for your USB memory stick.  But this is not perfect.  Most parts of erased filenames and their attributes may be hidden and remain in the filesystem.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_undeleting_deleted_but_still_open_files"/>9.7.10. Undeleting deleted but still open files</h3>
              </div>
            </div>
          </div>
          <p>Even if you have accidentally deleted a file, as long as that file is still being used by some application (read or write mode), it is possible to recover such a file.</p>
          <p>For example, try the following</p>
          <pre class="screen">$ echo foo &gt; bar
$ less bar
$ ps aux | grep ' less[ ]'
bozo    4775  0.0  0.0  92200   884 pts/8    S+   00:18   0:00 less bar
$ rm bar
$ ls -l /proc/4775/fd | grep bar
lr-x------ 1 bozo bozo 64 2008-05-09 00:19 4 -&gt; /home/bozo/bar (deleted)
$ cat /proc/4775/fd/4 &gt;bar
$ ls -l
-rw-r--r-- 1 bozo bozo 4 2008-05-09 00:25 bar
$ cat bar
foo</pre>
          <p>Execute on another terminal (when you have the <code class="literal">lsof</code> package installed) as follows.</p>
          <pre class="screen">$ ls -li bar
2228329 -rw-r--r-- 1 bozo bozo 4 2008-05-11 11:02 bar
$ lsof |grep bar|grep less
less 4775 bozo 4r REG 8,3 4 2228329 /home/bozo/bar
$ rm bar
$ lsof |grep bar|grep less
less 4775 bozo 4r REG 8,3 4 2228329 /home/bozo/bar (deleted)
$ cat /proc/4775/fd/4 &gt;bar
$ ls -li bar
2228302 -rw-r--r-- 1 bozo bozo 4 2008-05-11 11:05 bar
$ cat bar
foo</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_searching_all_hardlinks"/>9.7.11. Searching all hardlinks</h3>
              </div>
            </div>
          </div>
          <p>Files with hardlinks can be identified by "<code class="literal">ls -li</code>".</p>
          <pre class="screen">$ ls -li
total 0
2738405 -rw-r--r-- 1 root root 0 2008-09-15 20:21 bar
2738404 -rw-r--r-- 2 root root 0 2008-09-15 20:21 baz
2738404 -rw-r--r-- 2 root root 0 2008-09-15 20:21 foo</pre>
          <p>Both "<code class="literal">baz</code>" and "<code class="literal">foo</code>" have link counts of "2" (&gt;1) showing them to have hardlinks.  Their <a class="ulink" href="http://en.wikipedia.org/wiki/Inode">inode</a> numbers are common "2738404".  This means they are the same hardlinked file.  If you do not happen to find all hardlinked files by chance, you can search it by the <a class="ulink" href="http://en.wikipedia.org/wiki/Inode">inode</a>, e.g., "2738404" as the following.</p>
          <pre class="screen"># find /path/to/mount/point -xdev -inum 2738404</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_invisible_disk_space_consumption"/>9.7.12. Invisible disk space consumption</h3>
              </div>
            </div>
          </div>
          <p>All deleted but open files consume disk space although they are not visible from normal <span class="citerefentry"><span class="refentrytitle">du</span>(1)</span>.  They can be listed with their size by the following.</p>
          <pre class="screen"># lsof -s -X / |grep deleted</pre>
        </div>
      </div>
      <div class="section">
        <div class="titlepage">
          <div>
            <div>
              <h2 class="title"><a id="_data_encryption_tips"/>9.8. Data encryption tips</h2>
            </div>
          </div>
        </div>
        <p>With physical access to your PC, anyone can easily gain root privilege and access all the files on your PC (see <a class="xref" href="ch04.en.html#_securing_the_root_password" title="4.7.4. Securing the root password">Section 4.7.4, “Securing the root password”</a>).  This means that login password system can not secure your private and sensitive data against possible theft of your PC.  You must deploy data encryption technology to do it.  Although <a class="ulink" href="http://en.wikipedia.org/wiki/GNU_Privacy_Guard">GNU privacy guard</a> (see <a class="xref" href="ch10.en.html#_data_security_infrastructure" title="10.3. Data security infrastructure">Section 10.3, “Data security infrastructure”</a>) can encrypt files, it takes some user efforts.</p>
        <p><a class="ulink" href="http://en.wikipedia.org/wiki/Dm-crypt">dm-crypt</a> and <a class="ulink" href="http://ecryptfs.sourceforge.net/">eCryptfs</a> facilitates automatic data encryption natively via Linux kernel modules with minimal user efforts.</p>
        <div class="table">
          <a id="listofdataencryptionutilities"/>
          <p class="title">
            <strong>Table 9.24. List of data encryption utilities</strong>
          </p>
          <div class="table-contents">
            <table class="table" summary="List of data encryption utilities" border="1">
              <colgroup>
                <col style="text-align: left"/>
                <col style="text-align: left"/>
                <col style="text-align: left"/>
                <col style="text-align: left"/>
              </colgroup>
              <thead>
                <tr>
                  <th style="text-align: left">
    package
    </th>
                  <th style="text-align: left">
    popcon
    </th>
                  <th style="text-align: left">
    size
    </th>
                  <th style="text-align: left">
    description
    </th>
                </tr>
              </thead>
              <tbody>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/cryptsetup">
                <code class="literal">cryptsetup</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=cryptsetup">V:25, I:73</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/c/cryptsetup.html">355</a>
                  </td>
                  <td style="text-align: left">
    utilities for encrypted block device (<a class="ulink" href="http://en.wikipedia.org/wiki/Dm-crypt">dm-crypt</a> / <a class="ulink" href="http://en.wikipedia.org/wiki/Linux_Unified_Key_Setup">LUKS</a>)
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/cryptmount">
                <code class="literal">cryptmount</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=cryptmount">V:2, I:4</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/c/cryptmount.html">224</a>
                  </td>
                  <td style="text-align: left">
    utilities for encrypted block device (<a class="ulink" href="http://en.wikipedia.org/wiki/Dm-crypt">dm-crypt</a> / <a class="ulink" href="http://en.wikipedia.org/wiki/Linux_Unified_Key_Setup">LUKS</a>) with focus on mount/unmount by normal users
    </td>
                </tr>
                <tr>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.debian.org/sid/ecryptfs-utils">
                <code class="literal">ecryptfs-utils</code>
              </a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://qa.debian.org/popcon.php?package=ecryptfs-utils">V:5, I:8</a>
                  </td>
                  <td style="text-align: left">
                    <a class="ulink" href="http://packages.qa.debian.org/e/ecryptfs-utils.html">396</a>
                  </td>
                  <td style="text-align: left">
    utilities for encrypted stacked filesystem (<a class="ulink" href="http://ecryptfs.sourceforge.net/">eCryptfs</a>)
    </td>
                </tr>
              </tbody>
            </table>
          </div>
        </div>
        <br class="table-break"/>
        <p><a class="ulink" href="http://en.wikipedia.org/wiki/Dm-crypt">Dm-crypt</a> is a cryptographic filesystem using <a class="ulink" href="http://en.wikipedia.org/wiki/Device_mapper">device-mapper</a>. <a class="ulink" href="http://en.wikipedia.org/wiki/Device_mapper">Device-mapper</a> maps one block device to another.</p>
        <p><a class="ulink" href="http://ecryptfs.sourceforge.net/">eCryptfs</a> is another cryptographic filesystem using stacked filesystem.  Stacked filesystem stacks itself on top of an existing directory of a mounted filesystem.</p>
        <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
          <table border="0" summary="Caution">
            <tr>
              <td rowspan="2" align="center" valign="top">
                <img alt="[Caution]" src="images/caution.png"/>
              </td>
              <th align="left">Caution</th>
            </tr>
            <tr>
              <td align="left" valign="top">
                <p>Data encryption costs CPU time etc.  Please weigh its benefits and costs.</p>
              </td>
            </tr>
          </table>
        </div>
        <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
          <table border="0" summary="Note">
            <tr>
              <td rowspan="2" align="center" valign="top">
                <img alt="[Note]" src="images/note.png"/>
              </td>
              <th align="left">Note</th>
            </tr>
            <tr>
              <td align="left" valign="top">
                <p>Entire Debian system can be installed on a encrypted disk by the <a class="ulink" href="http://en.wikipedia.org/wiki/Debian-Installer">debian-installer</a> (lenny or newer) using <a class="ulink" href="http://en.wikipedia.org/wiki/Dm-crypt">dm-crypt</a>/<a class="ulink" href="http://en.wikipedia.org/wiki/Linux_Unified_Key_Setup">LUKS</a> and initramfs.</p>
              </td>
            </tr>
          </table>
        </div>
        <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
          <table border="0" summary="Tip">
            <tr>
              <td rowspan="2" align="center" valign="top">
                <img alt="[Tip]" src="images/tip.png"/>
              </td>
              <th align="left">Tip</th>
            </tr>
            <tr>
              <td align="left" valign="top">
                <p>See <a class="xref" href="ch10.en.html#_data_security_infrastructure" title="10.3. Data security infrastructure">Section 10.3, “Data security infrastructure”</a> for user space encryption utility: <a class="ulink" href="http://en.wikipedia.org/wiki/GNU_Privacy_Guard">GNU Privacy Guard</a>.</p>
              </td>
            </tr>
          </table>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_removable_disk_encryption_with_dm_crypt_luks"/>9.8.1. Removable disk encryption with dm-crypt/LUKS</h3>
              </div>
            </div>
          </div>
          <p>You can encrypt contents of removable mass devices, e.g. USB memory stick on "<code class="literal">/dev/sdx</code>", using <a class="ulink" href="http://en.wikipedia.org/wiki/Dm-crypt">dm-crypt</a>/<a class="ulink" href="http://en.wikipedia.org/wiki/Linux_Unified_Key_Setup">LUKS</a>.  You simply format it as the following.</p>
          <pre class="screen"># badblocks -c 1024 -s -w -t random -v /dev/sdx
# fdisk /dev/sdx
... "n" "p" "1" "return" "return" "w"
# cryptsetup luksFormat /dev/sdx1
...
# cryptsetup open --type luks /dev/sdx1 sdx1
...
# ls -l /dev/mapper/
total 0
crw-rw---- 1 root root  10, 60 2008-10-04 18:44 control
brw-rw---- 1 root disk 254,  0 2008-10-04 23:55 sdx1
# mkfs.vfat /dev/mapper/sdx1
...
# cryptsetup luksClose sdx1</pre>
          <p>Then, it can be mounted just like normal one on to "<code class="literal">/media/&lt;disk_label&gt;</code>", except for asking password (see <a class="xref" href="ch10.en.html#_removable_storage_device" title="10.1.7. Removable storage device">Section 10.1.7, “Removable storage device”</a>) under modern desktop environment, such as GNOME using <span class="citerefentry"><span class="refentrytitle">gnome-mount</span>(1)</span>.  The difference is that every data written to it is encrypted.  You may alternatively format media in different filesystem, e.g., ext4 with "<code class="literal">mkfs.ext4 /dev/mapper/sdx1</code>".</p>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>If you are really paranoid for the security of data, you may need to overwrite multiple times (the "<code class="literal">badblocks</code>" command in the above example).  This operation is very time consuming though.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_encrypted_swap_partition_with_dm_crypt"/>9.8.2. Encrypted swap partition with dm-crypt</h3>
              </div>
            </div>
          </div>
          <p>Let's assume that your original "<code class="literal">/etc/fstab</code>" contains the following.</p>
          <pre class="screen">/dev/sda7 swap sw 0 0</pre>
          <p>You can enable encrypted swap partition using <a class="ulink" href="http://en.wikipedia.org/wiki/Dm-crypt">dm-crypt</a> by as the following.</p>
          <pre class="screen"># aptitude install cryptsetup
# swapoff -a
# echo "cswap /dev/sda7 /dev/urandom swap" &gt;&gt; /etc/crypttab
# perl -i -p -e "s/\/dev\/sda7/\/dev\/mapper\/cswap/" /etc/fstab
# /etc/init.d/cryptdisks restart
 ...
# swapon -a</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_mounting_encrypted_disk_with_dm_crypt_luks"/>9.8.3. Mounting encrypted disk with dm-crypt/LUKS</h3>
              </div>
            </div>
          </div>
          <p>An encrypted disk partition created with dm-crypt/LUKS on "<code class="literal">/dev/sdc5</code>" can be mounted onto "<code class="literal">/mnt</code>" as follows:</p>
          <pre class="screen">$ sudo cryptsetup open /dev/sdc5 ninja --type luks
Enter passphrase for /dev/sdc5: ****
$ sudo lvm
lvm&gt; lvscan
  inactive          '/dev/ninja-vg/root' [13.52 GiB] inherit
  inactive          '/dev/ninja-vg/swap_1' [640.00 MiB] inherit
  ACTIVE            '/dev/goofy/root' [180.00 GiB] inherit
  ACTIVE            '/dev/goofy/swap' [9.70 GiB] inherit
lvm&gt; lvchange -a y /dev/ninja-vg/root
lvm&gt; exit
  Exiting.
$ sudo mount /dev/ninja-vg/root /mnt</pre>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_automatically_encrypting_files_with_ecryptfs"/>9.8.4. Automatically encrypting files with eCryptfs</h3>
              </div>
            </div>
          </div>
          <p>You can encrypt files written under "<code class="literal">~/Private/</code>" automatically using <a class="ulink" href="http://ecryptfs.sourceforge.net/">eCryptfs</a> and the <code class="literal">ecryptfs-utils</code> package.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
Run <span class="citerefentry"><span class="refentrytitle">ecryptfs-setup-private</span>(1)</span> and set up "<code class="literal">~/Private/</code>" by following prompts.
</p>
              </li>
              <li class="listitem">
                <p>
Activate "<code class="literal">~/Private/</code>" by running <span class="citerefentry"><span class="refentrytitle">ecryptfs-mount-private</span>(1)</span>.
</p>
              </li>
              <li class="listitem">
                <p>
Move sensitive data files to "<code class="literal">~/Private/</code>" and make symlinks as needed.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
Candidates: "<code class="literal">~/.fetchmailrc</code>", "<code class="literal">~/.ssh/identity</code>", "<code class="literal">~/.ssh/id_rsa</code>", "<code class="literal">~/.ssh/id_dsa</code>" and other files with "<code class="literal">go-rwx</code>"
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Move sensitive data directories to a subdirectory in "<code class="literal">~/Private/</code>" and make symlinks as needed.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
Candidates: "<code class="literal">~/.gnupg</code>" and other directories with "<code class="literal">go-rwx</code>"
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Create symlink from "<code class="literal">~/Desktop/Private/</code>" to "<code class="literal">~/Private/</code>" for easier desktop operations.
</p>
              </li>
              <li class="listitem">
                <p>
Deactivate "<code class="literal">~/Private/</code>" by running <span class="citerefentry"><span class="refentrytitle">ecryptfs-umount-private</span>(1)</span>.
</p>
              </li>
              <li class="listitem">
                <p>
Activate "<code class="literal">~/Private/</code>" by issuing "<code class="literal">ecryptfs-mount-private</code>" as you need encrypted data.
</p>
              </li>
            </ul>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Since <a class="ulink" href="http://ecryptfs.sourceforge.net/">eCryptfs</a> selectively encrypt only the sensitive files, its system cost is much less than using <a class="ulink" href="http://en.wikipedia.org/wiki/Dm-crypt">dm-crypt</a> on the entire root or "<code class="literal">/home</code>" device.  It does not require any special on-disk storage allocation effort but cannot keep all filesystem metadata confidential.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_automatically_mounting_ecryptfs"/>9.8.5. Automatically mounting eCryptfs</h3>
              </div>
            </div>
          </div>
          <p>If you use your login password for wrapping encryption keys, you can automate mounting eCryptfs via
<a class="ulink" href="http://en.wikipedia.org/wiki/Pluggable_Authentication_Modules">PAM (Pluggable Authentication Modules)</a>.</p>
          <p>Insert the following line just before "<code class="literal">pam_permit.so</code>" in "<code class="literal">/etc/pam.d/common-auth</code>".</p>
          <pre class="screen">auth required pam_ecryptfs.so unwrap</pre>
          <p>Insert the following line just at the last line in "<code class="literal">/etc/pam.d/common-session</code>".</p>
          <pre class="screen">session optional pam_ecryptfs.so unwrap</pre>
          <p>Insert the following line at first active line in "<code class="literal">/etc/pam.d/common-password</code>".</p>
          <pre class="screen">password required pam_ecryptfs.so</pre>
          <p>This is quite convenient.</p>
          <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Warning">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Warning]" src="images/warning.png"/>
                </td>
                <th align="left">Warning</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Configuration errors of <a class="ulink" href="http://en.wikipedia.org/wiki/Pluggable_Authentication_Modules">PAM</a> may lock you out of your own system. See <a class="xref" href="ch04.en.html" title="Chapter 4. Authentication">Chapter 4, <em>Authentication</em></a>.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Caution">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Caution]" src="images/caution.png"/>
                </td>
                <th align="left">Caution</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>If you use your login password for wrapping encryption keys, your encrypted data are as secure as your user login password (see <a class="xref" href="ch04.en.html#_good_password" title="4.3. Good password">Section 4.3, “Good password”</a>).  Unless you are careful to set up a <a class="ulink" href="http://en.wikipedia.org/wiki/Password_strength">strong password</a>, your data is at risk when someone runs <a class="ulink" href="http://en.wikipedia.org/wiki/Password_cracking">password cracking</a> software after stealing your laptop (see <a class="xref" href="ch04.en.html#_securing_the_root_password" title="4.7.4. Securing the root password">Section 4.7.4, “Securing the root password”</a>).</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
      </div>
      <div class="section">
        <div class="titlepage">
          <div>
            <div>
              <h2 class="title"><a id="_the_kernel"/>9.9. The kernel</h2>
            </div>
          </div>
        </div>
        <p>Debian distributes modularized <a class="ulink" href="http://en.wikipedia.org/wiki/Linux_kernel">Linux kernel</a> as packages for supported architectures.</p>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_linux_kernel_2_6_3_x"/>9.9.1. Linux kernel 2.6/3.x</h3>
              </div>
            </div>
          </div>
          <p>There are few notable features on Linux kernel 2.6/3.x compared to 2.4.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
Devices are created by the udev system (see <a class="xref" href="ch03.en.html#_the_udev_system" title="3.3. The udev system">Section 3.3, “The udev system”</a>).
</p>
              </li>
              <li class="listitem">
                <p>
Read/write accesses to IDE CD/DVD devices do not use the <code class="literal">ide-scsi</code> module.
</p>
              </li>
              <li class="listitem">
                <p>
Network packet filtering functions use <code class="literal">iptables</code> kernel modules.
</p>
              </li>
            </ul>
          </div>
          <p>The version bump from Linux 2.6.39 to Linux 3.0 is not about major technological changes but about the 20th anniversary.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_kernel_parameters"/>9.9.2. Kernel parameters</h3>
              </div>
            </div>
          </div>
          <p>Many Linux features are configurable via kernel parameters as follows.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
Kernel parameters initialized by the bootloader (see <a class="xref" href="ch03.en.html#_stage_2_the_boot_loader" title="3.1.2. Stage 2: the boot loader">Section 3.1.2, “Stage 2: the boot loader”</a>)
</p>
              </li>
              <li class="listitem">
                <p>
Kernel parameters changed by <span class="citerefentry"><span class="refentrytitle">sysctl</span>(8)</span> at runtime for ones accessible via sysfs (see <a class="xref" href="ch01.en.html#_procfs_and_sysfs" title="1.2.12. procfs and sysfs">Section 1.2.12, “procfs and sysfs”</a>)
</p>
              </li>
              <li class="listitem">
                <p>
Module parameters set by arguments of <span class="citerefentry"><span class="refentrytitle">modprobe</span>(8)</span> when a module is activated (see <a class="xref" href="ch09.en.html#_mounting_the_disk_image_file" title="9.6.3. Mounting the disk image file">Section 9.6.3, “Mounting the disk image file”</a>)
</p>
              </li>
            </ul>
          </div>
          <p>See "<code class="literal">kernel-parameters.txt(.gz)</code>" and other related documents in the Linux kernel documentation ("<code class="literal">/usr/share/doc/linux-doc-3.*/Documentation/filesystems/*</code>") provided by the <code class="literal">linux-doc-3.*</code> package.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_kernel_headers"/>9.9.3. Kernel headers</h3>
              </div>
            </div>
          </div>
          <p>Most <span class="strong"><strong>normal programs</strong></span> don't need kernel headers and in fact may break if you use them directly for compiling. They should be compiled against the headers in "<code class="literal">/usr/include/linux</code>" and "<code class="literal">/usr/include/asm</code>" provided by the <code class="literal">libc6-dev</code> package (created from the <code class="literal">glibc</code> source package) on the Debian system.</p>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>For compiling some kernel-specific programs such as the kernel modules from the external source and the automounter daemon (<code class="literal">amd</code>), you must include path to the corresponding kernel headers, e.g. "<code class="literal">-I/usr/src/linux-particular-version/include/</code>", to your command line. <span class="citerefentry"><span class="refentrytitle">module-assistant</span>(8)</span> (or its short form <code class="literal">m-a</code>) helps users to build and install module package(s) easily for one or more custom kernels.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_compiling_the_kernel_and_related_modules"/>9.9.4. Compiling the kernel and related modules</h3>
              </div>
            </div>
          </div>
          <p>Debian has its own method of compiling the kernel and related modules.</p>
          <div class="table">
            <a id="listofkeypackagenthedebiansystem"/>
            <p class="title">
              <strong>Table 9.25. List of key packages to be installed for the kernel recompilation on the Debian system</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of key packages to be installed for the kernel recompilation on the Debian system" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/build-essential">
                  <code class="literal">build-essential</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=build-essential">I:451</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/b/build-essential.html">20</a>
                    </td>
                    <td style="text-align: left">
    essential packages for building Debian packages: <code class="literal">make</code>, <code class="literal">gcc</code>, …
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/bzip2">
                  <code class="literal">bzip2</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=bzip2">V:238, I:933</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/b/bzip2.html">184</a>
                    </td>
                    <td style="text-align: left">
    compress and decompress utilities for bz2 files
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/libncurses5-dev">
                  <code class="literal">libncurses5-dev</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=libncurses5-dev">V:14, I:150</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/libn/libncurses5-dev.html">1027</a>
                    </td>
                    <td style="text-align: left">
    developer's libraries and docs for ncurses
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/git">
                  <code class="literal">git</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=git">V:259, I:420</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/g/git.html">28761</a>
                    </td>
                    <td style="text-align: left">
    git: distributed revision control system used by the Linux kernel
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/fakeroot">
                  <code class="literal">fakeroot</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=fakeroot">V:32, I:496</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/f/fakeroot.html">215</a>
                    </td>
                    <td style="text-align: left">
    provide fakeroot environment for building package as non-root
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/initramfs-tools">
                  <code class="literal">initramfs-tools</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=initramfs-tools">V:151, I:990</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/i/initramfs-tools.html">105</a>
                    </td>
                    <td style="text-align: left">
    tool to build an initramfs (Debian specific)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/dkms">
                  <code class="literal">dkms</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=dkms">V:70, I:207</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/dkms.html">282</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/Dynamic_Kernel_Module_Support">dynamic kernel module support (DKMS)</a> (generic)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/devscripts">
                  <code class="literal">devscripts</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=devscripts">V:10, I:66</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/devscripts.html">2070</a>
                    </td>
                    <td style="text-align: left">
    helper scripts for a Debian Package maintainer (Debian specific)
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <p>If you use <code class="literal">initrd</code> in <a class="xref" href="ch03.en.html#_stage_2_the_boot_loader" title="3.1.2. Stage 2: the boot loader">Section 3.1.2, “Stage 2: the boot loader”</a>, make sure to read the related information in <span class="citerefentry"><span class="refentrytitle">initramfs-tools</span>(8)</span>, <span class="citerefentry"><span class="refentrytitle">update-initramfs</span>(8)</span>, <span class="citerefentry"><span class="refentrytitle">mkinitramfs</span>(8)</span> and <span class="citerefentry"><span class="refentrytitle">initramfs.conf</span>(5)</span>.</p>
          <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Warning">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Warning]" src="images/warning.png"/>
                </td>
                <th align="left">Warning</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Do not put symlinks to the directories in the source tree (e.g. "<code class="literal">/usr/src/linux*</code>") from "<code class="literal">/usr/include/linux</code>" and "<code class="literal">/usr/include/asm</code>" when compiling the Linux kernel source. (Some outdated documents suggest this.)</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>When compiling the latest Linux kernel on the Debian <code class="literal">stable</code> system, the use of backported latest tools from the Debian <code class="literal">unstable</code> may be needed.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>The <a class="ulink" href="http://en.wikipedia.org/wiki/Dynamic_Kernel_Module_Support">dynamic kernel module support (DKMS)</a> is a new distribution independent framework designed to allow individual kernel modules to be upgraded without changing the whole kernel. This is used for the maintenance of out-of-tree modules.  This also makes it very easy to rebuild modules as you upgrade kernels.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_compiling_the_kernel_source_debian_kernel_team_recommendation"/>9.9.5. Compiling the kernel source: Debian Kernel Team recommendation</h3>
              </div>
            </div>
          </div>
          <p>For building custom kernel binary packages from the upstream kernel source, you should use the "<code class="literal">deb-pkg</code>" target provided by it.</p>
          <pre class="screen">$ sudo apt-get build-dep linux
$ cd /usr/src
$ wget http://www.kernel.org/pub/linux/kernel/v3.11/linux-&lt;version&gt;.tar.bz2
$ tar -xjvf linux-&lt;version&gt;.tar.bz2
$ cd linux-&lt;version&gt;
$ cp /boot/config-&lt;version&gt; .config
$ make menuconfig
 ...
$ make deb-pkg</pre>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>The linux-source-&lt;version&gt; package provides the Linux kernel source with Debian patches as "<code class="literal">/usr/src/linux-&lt;version&gt;.tar.bz2</code>".</p>
                </td>
              </tr>
            </table>
          </div>
          <p>For building specific binary packages from the Debian kernel source package, you should use the "<code class="literal">binary-arch_&lt;architecture&gt;_&lt;featureset&gt;_&lt;flavour&gt;</code>" targets in "<code class="literal">debian/rules.gen</code>".</p>
          <pre class="screen">$ sudo apt-get build-dep linux
$ apt-get source linux
$ cd linux-3.*
$ fakeroot make -f debian/rules.gen binary-arch_i386_none_686</pre>
          <p>See further information:</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
Debian Wiki: <a class="ulink" href="http://wiki.debian.org/KernelFAQ">KernelFAQ</a>
</p>
              </li>
              <li class="listitem">
                <p>
Debian Wiki: <a class="ulink" href="http://wiki.debian.org/DebianKernel">DebianKernel</a>
</p>
              </li>
              <li class="listitem">
                <p>
Debian Linux Kernel Handbook: <a class="ulink" href="http://kernel-handbook.alioth.debian.org">http://kernel-handbook.alioth.debian.org</a>
</p>
              </li>
            </ul>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_hardware_drivers_and_firmware"/>9.9.6. Hardware drivers and firmware</h3>
              </div>
            </div>
          </div>
          <p>The hardware driver is the code running on the target system. Most hardware drivers are available as free software now and are included in the normal Debian kernel packages in the <code class="literal">main</code> area.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p><a class="ulink" href="http://en.wikipedia.org/wiki/Graphics_processing_unit">GPU</a> driver
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
Intel GPU driver (<code class="literal">main</code>)
</p>
                    </li>
                    <li class="listitem">
                      <p>
AMD/ATI GPU driver (<code class="literal">main</code>)
</p>
                    </li>
                    <li class="listitem">
                      <p>
NVIDIA GPU driver (<code class="literal">main</code> for <a class="ulink" href="http://en.wikipedia.org/wiki/Nouveau_(software)">nouveau</a> driver, and <code class="literal">non-free</code> for binary-only drivers supported by the vendor.)
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p><a class="ulink" href="http://en.wikipedia.org/wiki/Softmodem">Softmodem</a> driver
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
martian-modem and sl-modem-dkms packages (<code class="literal">non-free</code>)
</p>
                    </li>
                  </ul>
                </div>
              </li>
            </ul>
          </div>
          <p>The firmware is the code or data loaded on the device (e.g., CPU <a class="ulink" href="http://en.wikipedia.org/wiki/Microcode">microcode</a>, rendering code running on GPU, or <a class="ulink" href="http://en.wikipedia.org/wiki/FPGA">FPGA</a> / <a class="ulink" href="http://en.wikipedia.org/wiki/Complex_programmable_logic_device">CPLD</a> data, …).  Some firmware packages are available as free software but many firmware packages are not available as free software since they contain sourceless binary data.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
firmware-linux-free (<code class="literal">main</code>)
</p>
              </li>
              <li class="listitem">
                <p>
firmware-linux-nonfree (<code class="literal">non-free</code>)
</p>
              </li>
              <li class="listitem">
                <p>
firmware-linux-* (<code class="literal">non-free</code>)
</p>
              </li>
              <li class="listitem">
                <p>
*-firmware (<code class="literal">non-free</code>)
</p>
              </li>
              <li class="listitem">
                <p>
intel-microcode (<code class="literal">non-free</code>)
</p>
              </li>
              <li class="listitem">
                <p>
amd64-microcode (<code class="literal">non-free</code>)
</p>
              </li>
            </ul>
          </div>
          <p>Please note that <code class="literal">non-free</code> and <code class="literal">contrib</code> packages are not part of the Debian system.  The access configuration to enable and to disable the <code class="literal">non-free</code> and <code class="literal">contrib</code> areas is described in <a class="xref" href="ch02.en.html#_debian_archive_basics" title="2.1.4. Debian archive basics">Section 2.1.4, “Debian archive basics”</a>.  You should be aware of negatives associated with the use of the <code class="literal">non-free</code> and <code class="literal">contrib</code> packages as described in <a class="xref" href="ch02.en.html#_debian_is_100_free_software" title="2.1.5. Debian is 100% free software">Section 2.1.5, “Debian is 100% free software”</a>.</p>
        </div>
      </div>
      <div class="section">
        <div class="titlepage">
          <div>
            <div>
              <h2 class="title"><a id="_virtualized_system"/>9.10. Virtualized system</h2>
            </div>
          </div>
        </div>
        <p>Use of virtualized system enables us to run multiple instances of system simultaneously on a single hardware.</p>
        <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
          <table border="0" summary="Tip">
            <tr>
              <td rowspan="2" align="center" valign="top">
                <img alt="[Tip]" src="images/tip.png"/>
              </td>
              <th align="left">Tip</th>
            </tr>
            <tr>
              <td align="left" valign="top">
                <p>See <a class="ulink" href="http://wiki.debian.org/SystemVirtualization">http://wiki.debian.org/SystemVirtualization</a>.</p>
              </td>
            </tr>
          </table>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_virtualization_tools"/>9.10.1. Virtualization tools</h3>
              </div>
            </div>
          </div>
          <p>There are several system <a class="ulink" href="http://en.wikipedia.org/wiki/Virtualization">virtualization</a> and <a class="ulink" href="http://en.wikipedia.org/wiki/Emulator">emulation</a> related packages in Debian beyond simple <a class="ulink" href="http://en.wikipedia.org/wiki/Chroot">chroot</a>.  Some packages also help you to setup such system.</p>
          <div class="table">
            <a id="listofvirtualizationtools"/>
            <p class="title">
              <strong>Table 9.26. List of virtualization tools</strong>
            </p>
            <div class="table-contents">
              <table class="table" summary="List of virtualization tools" border="1">
                <colgroup>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                  <col style="text-align: left"/>
                </colgroup>
                <thead>
                  <tr>
                    <th style="text-align: left">
    package
    </th>
                    <th style="text-align: left">
    popcon
    </th>
                    <th style="text-align: left">
    size
    </th>
                    <th style="text-align: left">
    description
    </th>
                  </tr>
                </thead>
                <tbody>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/schroot">
                  <code class="literal">schroot</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=schroot">V:6, I:10</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/schroot.html">2653</a>
                    </td>
                    <td style="text-align: left">
    specialized tool for executing Debian binary packages in chroot
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/sbuild">
                  <code class="literal">sbuild</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=sbuild">V:1, I:3</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/s/sbuild.html">283</a>
                    </td>
                    <td style="text-align: left">
    tool for building Debian binary packages from Debian sources
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/pbuilder">
                  <code class="literal">pbuilder</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=pbuilder">V:2, I:18</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/p/pbuilder.html">962</a>
                    </td>
                    <td style="text-align: left">
    personal package builder for Debian packages
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/debootstrap">
                  <code class="literal">debootstrap</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=debootstrap">V:6, I:68</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/debootstrap.html">259</a>
                    </td>
                    <td style="text-align: left">
    bootstrap a basic Debian system (written in sh)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/cdebootstrap">
                  <code class="literal">cdebootstrap</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=cdebootstrap">V:0, I:3</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/c/cdebootstrap.html">112</a>
                    </td>
                    <td style="text-align: left">
    bootstrap a Debian system (written in C)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/virt-manager">
                  <code class="literal">virt-manager</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=virt-manager">V:8, I:31</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/v/virt-manager.html">7426</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/Virtual_Machine_Manager">Virtual Machine Manager</a>: desktop application for managing virtual machines
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/libvirt-clients">
                  <code class="literal">libvirt-clients</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=libvirt-clients">V:25, I:47</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/libv/libvirt-clients.html">1907</a>
                    </td>
                    <td style="text-align: left">
    programs for the <a class="ulink" href="http://en.wikipedia.org/wiki/Libvirt">libvirt</a> library
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/bochs">
                  <code class="literal">bochs</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=bochs">V:0, I:1</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/b/bochs.html">4086</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/Bochs">Bochs</a>: IA-32 PC emulator
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/qemu">
                  <code class="literal">qemu</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=qemu">I:41</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/q/qemu.html">518</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a>: fast generic processor emulator
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/qemu-system">
                  <code class="literal">qemu-system</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=qemu-system">I:43</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/q/qemu-system.html">91</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a>: full system emulation binaries
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/qemu-user">
                  <code class="literal">qemu-user</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=qemu-user">V:2, I:42</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/q/qemu-user.html">70592</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a>: user mode emulation binaries
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/qemu-utils">
                  <code class="literal">qemu-utils</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=qemu-utils">V:8, I:94</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/q/qemu-utils.html">6657</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a>: utilities
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/qemu-kvm">
                  <code class="literal">qemu-kvm</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=qemu-kvm">V:18, I:68</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/q/qemu-kvm.html">100</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/Kernel-based_Virtual_Machine">KVM</a>: full virtualization on x86 hardware with the <a class="ulink" href="http://en.wikipedia.org/wiki/Hardware-assisted_virtualization">hardware-assisted virtualization</a></td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/virtualbox">
                  <code class="literal">virtualbox</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=virtualbox">V:51, I:64</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/v/virtualbox.html">72786</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/VirtualBox">VirtualBox</a>: x86 virtualization solution on i386 and amd64
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/xen-tools">
                  <code class="literal">xen-tools</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=xen-tools">V:0, I:7</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/x/xen-tools.html">666</a>
                    </td>
                    <td style="text-align: left">
    tools to manage debian <a class="ulink" href="http://en.wikipedia.org/wiki/Xen">XEN</a> virtual server
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/wine">
                  <code class="literal">wine</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=wine">V:25, I:106</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/w/wine.html">174</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/Wine_(software)">Wine</a>: Windows API Implementation (standard suite)
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/dosbox">
                  <code class="literal">dosbox</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=dosbox">V:3, I:21</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/dosbox.html">2755</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/DOSBox">DOSBox</a>: x86 emulator with Tandy/Herc/CGA/EGA/VGA/SVGA graphics, sound and DOS
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/dosemu">
                  <code class="literal">dosemu</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=dosemu">V:1, I:4</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/d/dosemu.html">4891</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/DOSEMU">DOSEMU</a>: The Linux DOS Emulator
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/vzctl">
                  <code class="literal">vzctl</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=vzctl">V:2, I:4</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/v/vzctl.html">1070</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/OpenVZ">OpenVZ</a> server virtualization solution - control tools
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/vzquota">
                  <code class="literal">vzquota</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=vzquota">V:2, I:4</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/v/vzquota.html">222</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://en.wikipedia.org/wiki/OpenVZ">OpenVZ</a> server virtualization solution - quota tools
    </td>
                  </tr>
                  <tr>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.debian.org/sid/lxc">
                  <code class="literal">lxc</code>
                </a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://qa.debian.org/popcon.php?package=lxc">V:8, I:13</a>
                    </td>
                    <td style="text-align: left">
                      <a class="ulink" href="http://packages.qa.debian.org/l/lxc.html">1297</a>
                    </td>
                    <td style="text-align: left"><a class="ulink" href="http://lxc.sourceforge.net/">Linux containers</a> user space tools
    </td>
                  </tr>
                </tbody>
              </table>
            </div>
          </div>
          <br class="table-break"/>
          <p>See Wikipedia article <a class="ulink" href="http://en.wikipedia.org/wiki/Comparison_of_platform_virtual_machines">Comparison of platform virtual machines</a> for detail comparison of different platform virtualization solutions.</p>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_virtualization_work_flow"/>9.10.2. Virtualization work flow</h3>
              </div>
            </div>
          </div>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Some functionalities described here are only available in <code class="literal">squeeze</code> or later.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Default Debian kernels support <a class="ulink" href="http://en.wikipedia.org/wiki/Kernel-based_Virtual_Machine">KVM</a> since <code class="literal">lenny</code>.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>Typical work flow for <a class="ulink" href="http://en.wikipedia.org/wiki/Virtualization">virtualization</a> involves several steps.</p>
          <div class="itemizedlist">
            <ul class="itemizedlist">
              <li class="listitem">
                <p>
Create an empty filesystem (a file tree or a disk image).
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
The file tree can be created by "<code class="literal">mkdir -p /path/to/chroot</code>".
</p>
                    </li>
                    <li class="listitem">
                      <p>
The raw disk image file can be created with <span class="citerefentry"><span class="refentrytitle">dd</span>(1)</span> (see <a class="xref" href="ch09.en.html#_making_the_disk_image_file" title="9.6.1. Making the disk image file">Section 9.6.1, “Making the disk image file”</a> and <a class="xref" href="ch09.en.html#_making_the_empty_disk_image_file" title="9.6.5. Making the empty disk image file">Section 9.6.5, “Making the empty disk image file”</a>).
</p>
                    </li>
                    <li class="listitem">
                      <p><span class="citerefentry"><span class="refentrytitle">qemu-img</span>(1)</span> can be used to create and convert disk image files supported by <a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a>.
</p>
                    </li>
                    <li class="listitem">
                      <p>
The raw and <a class="ulink" href="http://en.wikipedia.org/wiki/VMDK">VMDK</a> file format can be used as common format among virtualization tools.
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Mount the disk image with <span class="citerefentry"><span class="refentrytitle">mount</span>(8)</span> to the filesystem (optional).
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
For the raw disk image file, mount it as <a class="ulink" href="http://en.wikipedia.org/wiki/Loop_device">loop device</a> or <a class="ulink" href="http://en.wikipedia.org/wiki/Device_mapper">device mapper</a> devices (see <a class="xref" href="ch09.en.html#_mounting_the_disk_image_file" title="9.6.3. Mounting the disk image file">Section 9.6.3, “Mounting the disk image file”</a>).
</p>
                    </li>
                    <li class="listitem">
                      <p>
For disk images supported by <a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a>, mount them as <a class="ulink" href="http://en.wikipedia.org/wiki/Network_block_device">network block device</a> (see <a class="xref" href="ch09.en.html#_mounting_the_virtual_disk_image_file" title="9.10.3. Mounting the virtual disk image file">Section 9.10.3, “Mounting the virtual disk image file”</a>).
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Populate the target filesystem with required system data.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p>
The use of programs such as <code class="literal">debootstrap</code> and <code class="literal">cdebootstrap</code> helps with this process (see <a class="xref" href="ch09.en.html#_chroot_system" title="9.10.4. Chroot system">Section 9.10.4, “Chroot system”</a>).
</p>
                    </li>
                    <li class="listitem">
                      <p>
Use installers of OSs under the full system emulation.
</p>
                    </li>
                  </ul>
                </div>
              </li>
              <li class="listitem">
                <p>
Run a program under a virtualized environment.
</p>
                <div class="itemizedlist">
                  <ul class="itemizedlist">
                    <li class="listitem">
                      <p><a class="ulink" href="http://en.wikipedia.org/wiki/Chroot">chroot</a> provides basic virtualized environment enough to compile programs, run console applications, and run daemons in it.
</p>
                    </li>
                    <li class="listitem">
                      <p><a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a> provides cross-platform CPU emulation.
</p>
                    </li>
                    <li class="listitem">
                      <p><a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a> with <a class="ulink" href="http://en.wikipedia.org/wiki/Kernel-based_Virtual_Machine">KVM</a> provides full system emulation by the <a class="ulink" href="http://en.wikipedia.org/wiki/Hardware-assisted_virtualization">hardware-assisted virtualization</a>.
</p>
                    </li>
                    <li class="listitem">
                      <p><a class="ulink" href="http://en.wikipedia.org/wiki/VirtualBox">VirtualBox</a> provides full system emulation on i386 and amd64 with or without the <a class="ulink" href="http://en.wikipedia.org/wiki/Hardware-assisted_virtualization">hardware-assisted virtualization</a>.
</p>
                    </li>
                  </ul>
                </div>
              </li>
            </ul>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_mounting_the_virtual_disk_image_file"/>9.10.3. Mounting the virtual disk image file</h3>
              </div>
            </div>
          </div>
          <p>For the raw disk image file, see <a class="xref" href="ch09.en.html#_the_disk_image" title="9.6. The disk image">Section 9.6, “The disk image”</a>.</p>
          <p>For other virtual disk image files, you can use <span class="citerefentry"><span class="refentrytitle">qemu-nbd</span>(8)</span> to export them using <a class="ulink" href="http://en.wikipedia.org/wiki/Network_block_device">network block device</a> protocol and mount them using the <code class="literal">nbd</code> kernel module.</p>
          <p><span class="citerefentry"><span class="refentrytitle">qemu-nbd</span>(8)</span> supports disk formats supported by <a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a>: <a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a> supports following disk formats: raw, <a class="ulink" href="http://en.wikipedia.org/wiki/Qcow">qcow2, qcow</a>, <a class="ulink" href="http://en.wikipedia.org/wiki/VMDK">vmdk</a>, <a class="ulink" href="http://en.wikipedia.org/wiki/VirtualBox#Virtual_Desktop_Image">vdi</a>, <a class="ulink" href="http://en.wikipedia.org/wiki/Bochs">bochs</a>, cow (user-mode Linux copy-on-write), <a class="ulink" href="http://en.wikipedia.org/wiki/Parallels_Workstation">parallels</a>, <a class="ulink" href="http://en.wikipedia.org/wiki/Apple_Disk_Image">dmg</a>, <a class="ulink" href="http://en.wikipedia.org/wiki/Cloop">cloop</a>, <a class="ulink" href="http://en.wikipedia.org/wiki/VHD_(file_format)">vpc</a>, vvfat (virtual VFAT), and host_device.</p>
          <p>The <a class="ulink" href="http://en.wikipedia.org/wiki/Network_block_device">network block device</a> can support partitions in the same way as the <a class="ulink" href="http://en.wikipedia.org/wiki/Loop_device">loop device</a> (see <a class="xref" href="ch09.en.html#_mounting_the_disk_image_file" title="9.6.3. Mounting the disk image file">Section 9.6.3, “Mounting the disk image file”</a>).  You can mount the first partition of "<code class="literal">disk.img</code>" as follows.</p>
          <pre class="screen"># modprobe nbd max_part=16
# qemu-nbd -v -c /dev/nbd0 disk.img
...
# mkdir /mnt/part1
# mount /dev/nbd0p1 /mnt/part1</pre>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>You may export only the first partition of "<code class="literal">disk.img</code>" using "<code class="literal">-P 1</code>" option to <span class="citerefentry"><span class="refentrytitle">qemu-nbd</span>(8)</span>.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_chroot_system"/>9.10.4. Chroot system</h3>
              </div>
            </div>
          </div>
          <p><span class="citerefentry"><span class="refentrytitle">chroot</span>(8)</span> offers most basic way to run different instances of the GNU/Linux environment on a single system simultaneously without rebooting.</p>
          <div class="caution" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Caution">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Caution]" src="images/caution.png"/>
                </td>
                <th align="left">Caution</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Examples below assumes both parent system and chroot system share the same CPU architecture.</p>
                </td>
              </tr>
            </table>
          </div>
          <p>You can learn how to setup and use <span class="citerefentry"><span class="refentrytitle">chroot</span>(8)</span> by running <span class="citerefentry"><span class="refentrytitle">pbuilder</span>(8)</span> program under <span class="citerefentry"><span class="refentrytitle">script</span>(1)</span> as follows.</p>
          <pre class="screen">$ sudo mkdir /sid-root
$ sudo pbuilder --create --no-targz --debug --buildplace /sid-root</pre>
          <p>You see how <span class="citerefentry"><span class="refentrytitle">debootstrap</span>(8)</span> or <span class="citerefentry"><span class="refentrytitle">cdebootstrap</span>(1)</span> populate system data for <code class="literal">sid</code> environment under "<code class="literal">/sid-root</code>".</p>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>These <span class="citerefentry"><span class="refentrytitle">debootstrap</span>(8)</span> or <span class="citerefentry"><span class="refentrytitle">cdebootstrap</span>(1)</span> are used to <a class="ulink" href="http://www.debian.org/releases/stable/installmanual">install Debian</a> by the Debian Installer.  These can also be used to install Debian to a system without using a Debian install disk, but instead from another GNU/Linux distribution.</p>
                </td>
              </tr>
            </table>
          </div>
          <pre class="screen">$ sudo pbuilder --login --no-targz  --debug --buildplace /sid-root</pre>
          <p>You see how a system shell running under <code class="literal">sid</code> environment is created as the following.</p>
          <div class="orderedlist">
            <ol class="orderedlist">
              <li class="listitem">
                <p>
Copy local configuration (<code class="literal">"/etc/hosts</code>", <code class="literal">"/etc/hostname</code>", <code class="literal">"/etc/resolv.conf</code>")
</p>
              </li>
              <li class="listitem">
                <p>
Mount "<code class="literal">/proc</code>" filesystem
</p>
              </li>
              <li class="listitem">
                <p>
Mount "<code class="literal">/dev/pts</code>" filesystem
</p>
              </li>
              <li class="listitem">
                <p>
Create "<code class="literal">/usr/sbin/policy-rc.d</code>" which always exits with 101
</p>
              </li>
              <li class="listitem">
                <p>
Run "<code class="literal">chroot /sid-root bin/bash -c 'exec -a -bash bin/bash'</code>"
</p>
              </li>
            </ol>
          </div>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Some programs under chroot may require access to more files from the parent system to function than <code class="literal">pbuilder</code> provides.  For example, "<code class="literal">/sys</code>", "<code class="literal">/etc/passwd</code>", "<code class="literal">/etc/group</code>", "<code class="literal">/var/run/utmp</code>", "<code class="literal">/var/log/wtmp</code>", etc. may need to be bind-mounted or copied.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Note">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Note]" src="images/note.png"/>
                </td>
                <th align="left">Note</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>The "<code class="literal">/usr/sbin/policy-rc.d</code>" file prevents daemon programs to be started automatically on the Debian system.  See "<code class="literal">/usr/share/doc/sysv-rc/README.policy-rc.d.gz</code>".</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>The original purpose of the specialized chroot package, <code class="literal">pbuilder</code> is to construct a chroot system and builds a package inside the chroot.  It is an ideal system to use to check that a package's build-dependencies are correct, and to be sure that unnecessary and wrong build dependencies do not exist in the resulting package.</p>
                </td>
              </tr>
            </table>
          </div>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Similar <code class="literal">schroot</code> package may give you an idea to run <code class="literal">i386</code> chroot system under <code class="literal">amd64</code> parent system.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
        <div class="section">
          <div class="titlepage">
            <div>
              <div>
                <h3 class="title"><a id="_multiple_desktop_systems"/>9.10.5. Multiple desktop systems</h3>
              </div>
            </div>
          </div>
          <p>I recommend you to use <a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a> or <a class="ulink" href="http://en.wikipedia.org/wiki/VirtualBox">VirtualBox</a> on a Debian <code class="literal">stable</code> system to run multiple desktop systems safely using <a class="ulink" href="http://en.wikipedia.org/wiki/Virtualization">virtualization</a>.  These enable you to run desktop applications of Debian <code class="literal">unstable</code> and <code class="literal">testing</code> without usual risks associated with them.</p>
          <p>Since pure <a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a> is very slow, it is recommended to accelerate it with <a class="ulink" href="http://en.wikipedia.org/wiki/Kernel-based_Virtual_Machine">KVM</a> when the host system support it.</p>
          <p>The virtual disk image "<code class="literal">virtdisk.qcow2</code>" containing a Debian system for <a class="ulink" href="http://en.wikipedia.org/wiki/QEMU">QEMU</a> can be created using <a class="ulink" href="http://www.debian.org/distrib/netinst">debian-installer: Small CDs</a> as follows.</p>
          <pre class="screen">$ wget http://cdimage.debian.org/debian-cd/5.0.3/amd64/iso-cd/debian-503-amd64-netinst.iso
$ qemu-img create -f qcow2 virtdisk.qcow2 5G
$ qemu -hda virtdisk.qcow2 -cdrom debian-503-amd64-netinst.iso -boot d -m 256
...</pre>
          <p>See more tips at <a class="ulink" href="http://wiki.debian.org/QEMU">Debian wiki: QEMU</a>.</p>
          <p><a class="ulink" href="http://en.wikipedia.org/wiki/VirtualBox">VirtualBox</a> comes with <a class="ulink" href="http://en.wikipedia.org/wiki/Qt_(toolkit)">Qt</a> GUI tools and quite intuitive.  Its GUI and command line tools are explained in <a class="ulink" href="http://www.virtualbox.org/manual/UserManual.html">VirtualBox User Manual</a> and <a class="ulink" href="http://download.virtualbox.org/virtualbox/UserManual.pdf">VirtualBox User Manual (PDF)</a>.</p>
          <div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;">
            <table border="0" summary="Tip">
              <tr>
                <td rowspan="2" align="center" valign="top">
                  <img alt="[Tip]" src="images/tip.png"/>
                </td>
                <th align="left">Tip</th>
              </tr>
              <tr>
                <td align="left" valign="top">
                  <p>Running other GNU/Linux distributions such as <a class="ulink" href="http://www.ubuntu.com/">Ubuntu</a> and <a class="ulink" href="http://fedoraproject.org/">Fedora</a> under <a class="ulink" href="http://en.wikipedia.org/wiki/Virtualization">virtualization</a> is a great way to learn configuration tips.  Other proprietary OSs may be run nicely under this GNU/Linux <a class="ulink" href="http://en.wikipedia.org/wiki/Virtualization">virtualization</a>, too.</p>
                </td>
              </tr>
            </table>
          </div>
        </div>
      </div>
    </div>
    <div class="navfooter">
      <hr/>
      <table width="100%" summary="Navigation footer">
        <tr>
          <td align="left"><a accesskey="p" href="ch08.en.html"><img src="images/prev.png" alt="Prev"/></a> </td>
          <td align="center"> </td>
          <td align="right"> <a accesskey="n" href="ch10.en.html"><img src="images/next.png" alt="Next"/></a></td>
        </tr>
        <tr>
          <td align="left" valign="top">Chapter 8. I18N and L10N </td>
          <td align="center">
            <a accesskey="h" href="index.en.html">
              <img src="images/home.png" alt="Home"/>
            </a>
          </td>
          <td align="right" valign="top"> Chapter 10. Data management</td>
        </tr>
      </table>
    </div>
  </body>
</html>