/usr/share/debian-reference/ch12.es.html is in debian-reference-es 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 | <?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>Capítulo 12. Programación</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.es.html" title="Guía de referencia Debian"/>
<link rel="up" href="index.es.html" title="Guía de referencia Debian"/>
<link rel="prev" href="ch11.es.html" title="Capítulo 11. Conversión de datos"/>
<link rel="next" href="apa.es.html" title="Apéndice A. Appendix"/>
</head>
<body>
<div class="navheader">
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">Capítulo 12. Programación</th>
</tr>
<tr>
<td align="left"><a accesskey="p" href="ch11.es.html"><img src="images/prev.png" alt="Anterior"/></a> </td>
<th width="60%" align="center"> </th>
<td align="right"> <a accesskey="n" href="apa.es.html"><img src="images/next.png" alt="Siguiente"/></a></td>
</tr>
</table>
<hr/>
</div>
<div class="chapter">
<div class="titlepage">
<div>
<div>
<h1 class="title"><a id="_programming"/>Capítulo 12. Programación</h1>
</div>
</div>
</div>
<div class="toc">
<p>
<strong>Tabla de contenidos</strong>
</p>
<dl class="toc">
<dt>
<span class="section">
<a href="ch12.es.html#_the_shell_script">12.1. Los archivos de órdenes</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span class="section">
<a href="ch12.es.html#_posix_shell_compatibility">12.1.1. Compatibilidad del intérprete de órdenes POSIX</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_shell_parameters">12.1.2. Parámetros del intérprete de órdenes</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_shell_conditionals">12.1.3. Condiciones del intérprete de órdenes</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_shell_loops">12.1.4. Shell loops</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_the_shell_command_line_processing_sequence">12.1.5. The shell command-line processing sequence</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_utility_programs_for_shell_script">12.1.6. Utility programs for shell script</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_shell_script_dialog">12.1.7. Shell script dialog</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_shell_script_example_with_zenity">12.1.8. Shell script example with zenity</a>
</span>
</dt>
</dl>
</dd>
<dt>
<span class="section">
<a href="ch12.es.html#_make">12.2. Make</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_c">12.3. C</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span class="section">
<a href="ch12.es.html#_simple_c_program_gcc">12.3.1. Programa sencillo en C (gcc)</a>
</span>
</dt>
</dl>
</dd>
<dt>
<span class="section">
<a href="ch12.es.html#_debug">12.4. Depuración</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span class="section">
<a href="ch12.es.html#_basic_gdb_execution">12.4.1. Fundamentos de gdb</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_debugging_the_debian_package">12.4.2. Depurando un paquete Debian</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_obtaining_backtrace">12.4.3. Obtaining backtrace</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_advanced_gdb_commands">12.4.4. Advanced gdb commands</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_debugging_x_errors">12.4.5. Debugging X Errors</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_check_dependency_on_libraries">12.4.6. Check dependency on libraries</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_memory_leak_detection_tools">12.4.7. Memory leak detection tools</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_static_code_analysis_tools">12.4.8. Static code analysis tools</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_disassemble_binary">12.4.9. Disassemble binary</a>
</span>
</dt>
</dl>
</dd>
<dt>
<span class="section">
<a href="ch12.es.html#_flex_a_better_lex">12.5. Flex — a better Lex</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_bison_a_better_yacc">12.6. Bison — a better Yacc</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_autoconf">12.7. Autoconf</a>
</span>
</dt>
<dd>
<dl>
<dt>
<span class="section">
<a href="ch12.es.html#_compile_and_install_a_program">12.7.1. Compile and install a program</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_uninstall_program">12.7.2. Uninstall program</a>
</span>
</dt>
</dl>
</dd>
<dt>
<span class="section">
<a href="ch12.es.html#_perl_short_script_madness">12.8. Perl short script madness</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_web">12.9. Web</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_the_source_code_translation">12.10. The source code translation</a>
</span>
</dt>
<dt>
<span class="section">
<a href="ch12.es.html#_making_debian_package">12.11. Making Debian package</a>
</span>
</dt>
</dl>
</div>
<p>Algunos consejos para quién quiera aprender a programar en el sistema Debian
para trazar el código fuente. Aquí están los paquetes más importantes y los
paquetes de documentación más importantes para la programación.</p>
<div class="table">
<a id="listofpackagestohelpprograming"/>
<p class="title">
<strong>Tabla 12.1. Lista de paquetes que ayudan a la programación</strong>
</p>
<div class="table-contents">
<table class="table" summary="Lista de paquetes que ayudan a la programación" 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">
paquete
</th>
<th style="text-align: left">
popularidad
</th>
<th style="text-align: left">
tamaño
</th>
<th style="text-align: left">
documentación
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/autoconf">
<code class="literal">autoconf</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=autoconf">V:29, I:226</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/a/autoconf.html">1868</a>
</td>
<td style="text-align: left">
"<code class="literal">info autoconf</code>" proporcionado con
<code class="literal">autoconf-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/automake">
<code class="literal">automake</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=automake">V:27, I:220</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/a/automake.html">1707</a>
</td>
<td style="text-align: left">
"<code class="literal">info automake</code>" proporcionado con
<code class="literal">automake1.10-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/bash"> <code class="literal">bash</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=bash">V:853, I:999</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/b/bash.html">5799</a>
</td>
<td style="text-align: left">
"<code class="literal">info bash</code>" proporcionado con <code class="literal">bash-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/bison"> <code class="literal">bison</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=bison">V:10, I:113</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/b/bison.html">2061</a>
</td>
<td style="text-align: left">
"<code class="literal">info bison</code>" proporcionado con
<code class="literal">bison-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/cpp"> <code class="literal">cpp</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=cpp">V:394, I:806</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/c/cpp.html">41</a>
</td>
<td style="text-align: left">
"<code class="literal">info cpp</code>" proporcionado con <code class="literal">cpp-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/ddd"> <code class="literal">ddd</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=ddd">V:1, I:13</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/d/ddd.html">3965</a>
</td>
<td style="text-align: left">
"<code class="literal">info ddd</code>" proporcionado por <code class="literal">ddd-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/exuberant-ctags">
<code class="literal">exuberant-ctags</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=exuberant-ctags">V:7, I:38</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/e/exuberant-ctags.html">333</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">exuberant-ctags</span>(1)</span>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/flex"> <code class="literal">flex</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=flex">V:10, I:101</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/f/flex.html">1174</a>
</td>
<td style="text-align: left">
"<code class="literal">info flex</code>" proporcionado por <code class="literal">flex-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/gawk"> <code class="literal">gawk</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=gawk">V:355, I:478</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/g/gawk.html">2199</a>
</td>
<td style="text-align: left">
"<code class="literal">info gawk</code>" proporcionado por <code class="literal">gawk-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/gcc"> <code class="literal">gcc</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=gcc">V:148, I:606</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/g/gcc.html">43</a>
</td>
<td style="text-align: left">
"<code class="literal">info gcc</code>" proporcionado por <code class="literal">gcc-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/gdb"> <code class="literal">gdb</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=gdb">V:21, I:140</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/g/gdb.html">7983</a>
</td>
<td style="text-align: left">
"<code class="literal">info gdb</code>" proporcionado por <code class="literal">gdb-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/gettext">
<code class="literal">gettext</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=gettext">V:53, I:367</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/g/gettext.html">7076</a>
</td>
<td style="text-align: left">
"<code class="literal">info gettext</code>" proporcionado por
<code class="literal">gettext-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/gfortran">
<code class="literal">gfortran</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=gfortran">V:20, I:63</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/g/gfortran.html">16</a>
</td>
<td style="text-align: left">
"<code class="literal">info gfortran</code>" proporcionado por
<code class="literal">gfortran-doc</code> (Fortran 95)
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/fpc"> <code class="literal">fpc</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=fpc">I:4</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/f/fpc.html">113</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">fpc</span>(1)</span>
y html por <code class="literal">fp-docs</code> (Pascal)
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/glade"> <code class="literal">glade</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=glade">V:1, I:12</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/g/glade.html">2209</a>
</td>
<td style="text-align: left">
proporciona ayuda por medio del menú (Constructor UI)
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/libc6"> <code class="literal">libc6</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=libc6">V:933, I:999</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/libc/libc6.html">10679</a>
</td>
<td style="text-align: left">
"<code class="literal">info libc</code>" proporcionado por
<code class="literal">glibc-doc</code> y <code class="literal">glibc-doc-reference</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/make"> <code class="literal">make</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=make">V:154, I:622</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/m/make.html">1211</a>
</td>
<td style="text-align: left">
"<code class="literal">info make</code>" proporcionado por <code class="literal">make-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/xutils-dev">
<code class="literal">xutils-dev</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=xutils-dev">V:2, I:18</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/x/xutils-dev.html">1466</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">imake</span>(1)</span>,
<span class="citerefentry"><span class="refentrytitle">xmkmf</span>(1)</span>,
etc.
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/mawk"> <code class="literal">mawk</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=mawk">V:371, I:997</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/m/mawk.html">183</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">mawk</span>(1)</span>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/perl"> <code class="literal">perl</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=perl">V:610, I:996</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/p/perl.html">651</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">perl</span>(1)</span>
y páginas html proporcionadas por <code class="literal">perl-doc</code> y
<code class="literal">perl-doc-html</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/python">
<code class="literal">python</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=python">V:683, I:988</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/p/python.html">648</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">python</span>(1)</span>
y páginas html proporcionado por <code class="literal">python-doc</code></td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/tcl8.4">
<code class="literal">tcl8.4</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=tcl8.4">V:3, I:50</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/t/tcl8.4.html">NOT_FOUND</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">tcl</span>(3)</span>
y páginas de manual detalladas proporcionadas por
<code class="literal">tcl8.4-doc</code></td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/tk8.4"> <code class="literal">tk8.4</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=tk8.4">V:1, I:31</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/t/tk8.4.html">NOT_FOUND</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">tk</span>(3)</span>
y páginas de manual detalladas proporcionados por
<code class="literal">tk8.4-doc</code></td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/ruby"> <code class="literal">ruby</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=ruby">V:103, I:321</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/r/ruby.html">38</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">ruby</span>(1)</span>
y la referencia interactiva proporcionada por <code class="literal">ri</code></td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/vim"> <code class="literal">vim</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=vim">V:118, I:393</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/v/vim.html">2374</a>
</td>
<td style="text-align: left">
ayuda(F1) del menú proporacionado por <code class="literal">vim-doc</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/susv2"> <code class="literal">susv2</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=susv2">I:0</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/s/susv2.html">15</a>
</td>
<td style="text-align: left">
cumple "<a class="ulink" href="http://www.unix.org/version2/">La Especificación Única
de UNIX v2</a>"
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/susv3"> <code class="literal">susv3</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=susv3">I:0</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/s/susv3.html">15</a>
</td>
<td style="text-align: left">
cumple "<a class="ulink" href="http://www.unix.org/version3/">La Especificación Única
de UNIX v3</a>"
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>Las referencia en línea está disponible escribiendo by typing "<code class="literal">man
nombre</code>" tras instalar los paquetes <code class="literal">manpages</code> y
<code class="literal">manpages-dev</code>. La referencia en línea para las
herramientas GNU están disponibles escribiendo "<code class="literal">info
nombre_de_programa</code>" después de instalar los paquetes
correspondientes de documentación. Pude necesitar incluir los repositorios
<code class="literal">contrib</code> y <code class="literal">non-free</code> además del
repositorio <code class="literal">main</code> ya que una parte de la documentación
GFDL no se cosidera que cumple con DFSG.</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="[Aviso]" src="images/warning.png"/>
</td>
<th align="left">Aviso</th>
</tr>
<tr>
<td align="left" valign="top">
<p>No use"<code class="literal">test</code>" como nombre de un archivo ejecutable.
"<code class="literal">test</code>" es una órden interna del intérprete de órdenes.</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="[Atención]" src="images/caution.png"/>
</td>
<th align="left">Atención</th>
</tr>
<tr>
<td align="left" valign="top">
<p>Usted puede instalar programas de software directametne compilado de la
fuente en "<code class="literal">/usr/local</code>" o "<code class="literal">/opt</code>" para
evitar la colisión con los programas del sistema.</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="[Sugerencia]" src="images/tip.png"/>
</td>
<th align="left">Sugerencia</th>
</tr>
<tr>
<td align="left" valign="top">
<p><a class="ulink" href="http://www.99-bottles-of-beer.net/">Los ejemplos de código para
crear "La canción de 99 botellas de Cerveza"</a> le aportará buenas
ideas para pácticamente cualquier lenguaje de programación.</p>
</td>
</tr>
</table>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_the_shell_script"/>12.1. Los archivos de órdenes</h2>
</div>
</div>
</div>
<p>Un <a class="ulink" href="http://es.wikipedia.org/wiki/Script_(informática)">archivo de órdenes</a> es un archivo de
texto co el bit de ejecución activado y contiene órdenes con el formato
siguiente.</p>
<pre class="screen">#!/bin/sh
... líneas de órdenes</pre>
<p>La primera línea determina el intérprete del shell que se encarga de leer y
ejecutar el contenido del archivo.</p>
<p>La lectura de archivos de órdenes es la <span class="strong"><strong>mejor</strong></span> manera de entender como funciona un sistema
tipo Unix. Aquí, doy algunos apuntes para la programación de archivos de
órdenes. Consulte "Los errores de los archivos de órdenes" (<a class="ulink" href="http://www.greenend.org.uk/rjk/2001/04/shell.html">http://www.greenend.org.uk/rjk/2001/04/shell.html</a>)
para aprender los errores más comunes.</p>
<p>No como el modo interactivo de la consola (see <a class="xref" href="ch01.es.html#_the_simple_shell_command" title="1.5. Órdenes simples del intérpete de órdenes">Sección 1.5, “Órdenes simples del intérpete de órdenes”</a> and <a class="xref" href="ch01.es.html#_unix_like_text_processing" title="1.6. Procesamiento de texto al estilo Unix">Sección 1.6, “Procesamiento de texto al estilo Unix”</a>) los archivos de órdenes se usan
generalmente parámetros, condiciones e iteraciones.</p>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_posix_shell_compatibility"/>12.1.1. Compatibilidad del intérprete de órdenes POSIX</h3>
</div>
</div>
</div>
<p>Muchos de los archivos de órdenes pueden ser interpretados por un intérprete
<a class="ulink" href="http://es.wikipedia.org/wiki/POSIX">POSIX</a> (consulte <a class="xref" href="ch01.es.html#list-of-shell-programs" title="Tabla 1.13. Lista de intérpretes de órdenes">Tabla 1.13, “Lista de intérpretes de órdenes”</a>). El intérprete de órdenes del sistema
por defecto es "<code class="literal">/bin/sh</code>" el cual es un enlace simbólico
que referencia al programa actual.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p><span class="citerefentry"><span class="refentrytitle">bash</span>(1)</span>
para <code class="literal">lenny</code> o más antiguo
</p>
</li>
<li class="listitem">
<p><span class="citerefentry"><span class="refentrytitle">dash</span>(1)</span>
para <code class="literal">squeeze</code> o más nuevo
</p>
</li>
</ul>
</div>
<p>Evite escribir archivos de órdenes con particularidades de <span class="strong"><strong>bash</strong></span> o <span class="strong"><strong>zs</strong></span> para
hacerlo portable entre intérpretes de órdenes POSIX. Puede comprobaro
utilizando
<span class="citerefentry"><span class="refentrytitle">checkbashisms</span>(1)</span>.</p>
<div class="table">
<a id="listoftypicalbashisms"/>
<p class="title">
<strong>Tabla 12.2. Enumeración de particularidades de bash</strong>
</p>
<div class="table-contents">
<table class="table" summary="Enumeración de particularidades de bash" border="1">
<colgroup>
<col style="text-align: left"/>
<col style="text-align: left"/>
</colgroup>
<thead>
<tr>
<th style="text-align: left">
Bien: POSIX
</th>
<th style="text-align: left">
Mal: bashism
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<code class="literal">if [ "$foo" = "$bar" ] ; then …</code>
</td>
<td style="text-align: left">
<code class="literal">if [ "$foo" == "$bar" ] ; then …</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">diff -u archivo.c.orig archivo.c</code>
</td>
<td style="text-align: left">
<code class="literal">diff -u archivo.c{.orig,}</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">mkdir /foobar /foobaz</code>
</td>
<td style="text-align: left">
<code class="literal">mkdir /foo{bar,baz}</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">funcname() { … }</code>
</td>
<td style="text-align: left">
<code class="literal">function funcname() { … }</code>
</td>
</tr>
<tr>
<td style="text-align: left">
octal format: "<code class="literal">\377</code>"
</td>
<td style="text-align: left">
formato hexadecimal: "<code class="literal">\xff</code>"
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>La órden "<code class="literal">echo</code>" debe utilizarse con cuidado ya que su
implementación cambia entre la órden interna y la externa.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
Evite utilizar cualquier opción excepto <code class="literal">-n</code>".
</p>
</li>
<li class="listitem">
<p>
Evite utilizar secuencias de escape en una cadena ya que su tratamiento
varia.
</p>
</li>
</ul>
</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="[Nota]" src="images/note.png"/>
</td>
<th align="left">Nota</th>
</tr>
<tr>
<td align="left" valign="top">
<p>Ya que la opción "<code class="literal">-n</code>" <span class="strong"><strong>no</strong></span> pertenece realmente a la sintáxis POSIX es
aceptada normalmente.</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="[Sugerencia]" src="images/tip.png"/>
</td>
<th align="left">Sugerencia</th>
</tr>
<tr>
<td align="left" valign="top">
<p>Utilice la órden "<code class="literal">printf</code>" en vez de la órden
"<code class="literal">echo</code>" si necesita incluir secuencias de caracteres en
las cadenas de caracteres de salida.</p>
</td>
</tr>
</table>
</div>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_shell_parameters"/>12.1.2. Parámetros del intérprete de órdenes</h3>
</div>
</div>
</div>
<p>Frecuentemente son utilizados por el intérprete de órdenes parámetros
especiales</p>
<div class="table">
<a id="listofshellparameters"/>
<p class="title">
<strong>Tabla 12.3. Enumeración de los parámetros de intérprete de órdenes</strong>
</p>
<div class="table-contents">
<table class="table" summary="Enumeración de los parámetros de intérprete de órdenes" border="1">
<colgroup>
<col style="text-align: left"/>
<col style="text-align: left"/>
</colgroup>
<thead>
<tr>
<th style="text-align: left">
parámetro del intérprete de órdenes
</th>
<th style="text-align: left">
valor
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<code class="literal">$0</code>
</td>
<td style="text-align: left">
nombre del archivo de órdenes
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">$1</code>
</td>
<td style="text-align: left">
primer argumento del archivo de órdenes
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">$9</code>
</td>
<td style="text-align: left">
noveno argumento del archivo de órdenes
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">$#</code>
</td>
<td style="text-align: left">
parámetro posicionado en el número
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">"$*"</code>
</td>
<td style="text-align: left">
<code class="literal">"$1 $2 $3 $4 … "</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">"$@"</code>
</td>
<td style="text-align: left">
<code class="literal">"$1" "$2" "$3" "$4" …</code>
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">$?</code>
</td>
<td style="text-align: left">
estado de finalización de la órden más reciente
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">$$</code>
</td>
<td style="text-align: left">
PID de este archivo de órdenes
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">$!</code>
</td>
<td style="text-align: left">
PID del trabajo en segundo plano que se ha iniciado más recientemente
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>Las<span class="strong"><strong>expansiones de parámetros</strong></span>
fundamentales que debe recordar son las que se muestran.</p>
<div class="table">
<a id="listofshellparameterexpansions"/>
<p class="title">
<strong>Tabla 12.4. Enumeración de expansiones de parámetros del intérprete de órdenes</strong>
</p>
<div class="table-contents">
<table class="table" summary="Enumeración de expansiones de parámetros del intérprete de órdenes" 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">
forma de expresión del parámetro
</th>
<th style="text-align: left">
valor si <code class="literal">var</code> esta activado
</th>
<th style="text-align: left">
valor si <code class="literal">var</code> no está asignado
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<code class="literal">${var:-string}</code>
</td>
<td style="text-align: left">
"<code class="literal">$var</code>"
</td>
<td style="text-align: left">
"<code class="literal">string</code>"
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">${var:+string}</code>
</td>
<td style="text-align: left">
"<code class="literal">string</code>"
</td>
<td style="text-align: left">
"<code class="literal">null</code>"
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">${var:=string}</code>
</td>
<td style="text-align: left">
"<code class="literal">$var</code>"
</td>
<td style="text-align: left">
"<code class="literal">string</code>" (y ejecuta "<code class="literal">var=string</code>")
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">${var:?string}</code>
</td>
<td style="text-align: left">
"<code class="literal">$var</code>"
</td>
<td style="text-align: left">
echo "<code class="literal">string</code>" a <span class="strong"><strong>stderr</strong></span>
(y finalizar con error)
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>Aquí, el símbolo "<code class="literal">:</code>" en todos estos operadores es ahora
opcional.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p><span class="strong"><strong>con</strong></span> "<code class="literal">:</code>" el operador =
comprueba que <span class="strong"><strong>existe</strong></span> y <span class="strong"><strong>no es null</strong></span>
</p>
</li>
<li class="listitem">
<p><span class="strong"><strong>sin</strong></span> "<code class="literal">:</code>" el operador =
comprueba unicamente si <span class="strong"><strong>existe</strong></span>
</p>
</li>
</ul>
</div>
<div class="table">
<a id="listofkeyshellpatersubstitutions"/>
<p class="title">
<strong>Tabla 12.5. Enumeración de las sustituciones clave de parámetros del intérprete de
órdenes</strong>
</p>
<div class="table-contents">
<table class="table" summary="Enumeración de las sustituciones clave de parámetros del intérprete de órdenes" border="1">
<colgroup>
<col style="text-align: left"/>
<col style="text-align: left"/>
</colgroup>
<thead>
<tr>
<th style="text-align: left">
formulario de sustitución del parámetro
</th>
<th style="text-align: left">
resultado
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<code class="literal">${var%suffix}</code>
</td>
<td style="text-align: left">
elimina patrón del sufijo más pequeño
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">${var%%suffix}</code>
</td>
<td style="text-align: left">
elimina el patrón del sufijo más largo
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">${var#prefix}</code>
</td>
<td style="text-align: left">
elimina el patrón del prefijo más pequeño
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">${var##prefix}</code>
</td>
<td style="text-align: left">
elimina el patrón del prefijo más largo
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_shell_conditionals"/>12.1.3. Condiciones del intérprete de órdenes</h3>
</div>
</div>
</div>
<p>Cada comando devuelve un <span class="strong"><strong>estado de salida</strong></span>
que puede usarse para expresioneos condicionales.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
Éxito: 0 ("Verdadero")
</p>
</li>
<li class="listitem">
<p>
Error: no 0 ("Falso")
</p>
</li>
</ul>
</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="[Nota]" src="images/note.png"/>
</td>
<th align="left">Nota</th>
</tr>
<tr>
<td align="left" valign="top">
<p>"0" in the shell conditional context means "True", while "0" in the C
conditional context means "False".</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="[Nota]" src="images/note.png"/>
</td>
<th align="left">Nota</th>
</tr>
<tr>
<td align="left" valign="top">
<p>"<code class="literal">[</code>" is the equivalent of the <code class="literal">test</code>
command, which evaluates its arguments up to "<code class="literal">]</code>" as a
conditional expression.</p>
</td>
</tr>
</table>
</div>
<p>Basic <span class="strong"><strong>conditional idioms</strong></span> to remember are
the following.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
"<code class="literal"><command> && <if_success_run_this_command_too>
|| true</code>"
</p>
</li>
<li class="listitem">
<p>
"<code class="literal"><command> || <if_not_success_run_this_command_too> ||
true</code>"
</p>
</li>
<li class="listitem">
<p>
A multi-line script snippet as the following
</p>
</li>
</ul>
</div>
<pre class="screen">if [ <conditional_expression> ]; then
<if_success_run_this_command>
else
<if_not_success_run_this_command>
fi</pre>
<p>Here trailing "<code class="literal">|| true</code>" was needed to ensure this shell
script does not exit at this line accidentally when shell is invoked with
"<code class="literal">-e</code>" flag.</p>
<div class="table">
<a id="listoffilecompartionalexpression"/>
<p class="title">
<strong>Tabla 12.6. List of file comparison operators in the conditional expression</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of file comparison operators in the conditional expression" border="1">
<colgroup>
<col style="text-align: left"/>
<col style="text-align: left"/>
</colgroup>
<thead>
<tr>
<th style="text-align: left">
ecuación
</th>
<th style="text-align: left">
condition to return logical true
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<code class="literal">-e <file></code>
</td>
<td style="text-align: left">
<file> exists
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">-d <file></code>
</td>
<td style="text-align: left">
<file> exists and is a directory
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">-f <file></code>
</td>
<td style="text-align: left">
<file> exists and is a regular file
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">-w <file></code>
</td>
<td style="text-align: left">
<file> exists and is writable
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">-x <file></code>
</td>
<td style="text-align: left">
<file> exists and is executable
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal"><file1> -nt <file2></code>
</td>
<td style="text-align: left">
<file1> is newer than <file2> (modification)
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal"><file1> -ot <file2></code>
</td>
<td style="text-align: left">
<file1> is older than <file2> (modification)
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal"><file1> -ef <file2></code>
</td>
<td style="text-align: left">
<file1> and <file2> are on the same device and the same inode
number
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<div class="table">
<a id="listofstringcomptionalexpression"/>
<p class="title">
<strong>Tabla 12.7. List of string comparison operators in the conditional expression</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of string comparison operators in the conditional expression" border="1">
<colgroup>
<col style="text-align: left"/>
<col style="text-align: left"/>
</colgroup>
<thead>
<tr>
<th style="text-align: left">
ecuación
</th>
<th style="text-align: left">
condition to return logical true
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<code class="literal">-z <str></code>
</td>
<td style="text-align: left">
la longitud de <str> es cero
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">-n <str></code>
</td>
<td style="text-align: left">
la longitud de <str> no es cero
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal"><str1> = <str2></code>
</td>
<td style="text-align: left">
<str1> and <str2> are equal
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal"><str1> != <str2></code>
</td>
<td style="text-align: left">
<str1> y <str2> no son iguales
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal"><str1> < <str2></code>
</td>
<td style="text-align: left">
<str1> sorts before <str2> (locale dependent)
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal"><str1> > <str2></code>
</td>
<td style="text-align: left">
<str1> sorts after <str2> (locale dependent)
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>Los operadores <span class="strong"><strong>aritméticos</strong></span> de comparación
de enteros en la expresión original son "<code class="literal">-eq</code>",
"<code class="literal">-ne</code>", "<code class="literal">-lt</code>",
"<code class="literal">-le</code>", "<code class="literal">-gt</code>" y
"<code class="literal">-ge</code>".</p>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_shell_loops"/>12.1.4. Shell loops</h3>
</div>
</div>
</div>
<p>There are several loop idioms to use in POSIX shell.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
"<code class="literal">for x in foo1 foo2 … ; do comand0 ; done</code>" asigna
secuencialmente elementos de la lista "<code class="literal">foo1 foo2 …</code>" a la
variable "<code class="literal">x</code>" y ejecuta "<code class="literal">comando</code>".
</p>
</li>
<li class="listitem">
<p>
"<code class="literal">while condición ; do comando ; done</code>" repite
"<code class="literal">comando</code>" mientras "<code class="literal">condición</code>" sea
verdadero.
</p>
</li>
<li class="listitem">
<p>
"<code class="literal">until condición ; do comando ; done</code>" repite
"<code class="literal">comando</code>" mientras "<code class="literal">condición</code>" no sea
verdadero.
</p>
</li>
<li class="listitem">
<p>
"<code class="literal">break</code>" permite salir del bucle.
</p>
</li>
<li class="listitem">
<p>
"<code class="literal">continue</code>" permite continuar con la próxima iteración del
bucle.
</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="[Sugerencia]" src="images/tip.png"/>
</td>
<th align="left">Sugerencia</th>
</tr>
<tr>
<td align="left" valign="top">
<p>The <a class="ulink" href="https://es.wikipedia.org/wiki/C_(lenguaje_de_programación)">C</a>-language like numeric iteration can be
realized by using
<span class="citerefentry"><span class="refentrytitle">seq</span>(1)</span>
as the "<code class="literal">foo1 foo2 …</code>" generator.</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="[Sugerencia]" src="images/tip.png"/>
</td>
<th align="left">Sugerencia</th>
</tr>
<tr>
<td align="left" valign="top">
<p>Consulta <a class="xref" href="ch09.es.html#_repeating_a_command_looping_over_files" title="9.3.9. Repetición de una órden sobre archivos">Sección 9.3.9, “Repetición de una órden sobre archivos”</a>.</p>
</td>
</tr>
</table>
</div>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_the_shell_command_line_processing_sequence"/>12.1.5. The shell command-line processing sequence</h3>
</div>
</div>
</div>
<p>The shell processes a script roughly as the following sequence.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
The shell reads a line.
</p>
</li>
<li class="listitem">
<p>
The shell groups a part of the line as <span class="strong"><strong>one
token</strong></span> if it is within <code class="literal">"…"</code> or
<code class="literal">'…'</code>.
</p>
</li>
<li class="listitem">
<p>
The shell splits other part of a line into <span class="strong"><strong>tokens</strong></span> by the following.
</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
Whitespaces: <code class="literal"><space> <tab> <newline></code>
</p>
</li>
<li class="listitem">
<p>
Metacharacters: <code class="literal">< > | ; & ( )</code>
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
The shell checks the <span class="strong"><strong>reserved word</strong></span> for
each token to adjust its behavior if not within <code class="literal">"…"</code> or
<code class="literal">'…'</code>.
</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p><span class="strong"><strong>palabras reservadas</strong></span>: <code class="literal">if then
elif else fi for in while unless do done case esac</code></p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
The shell expands <span class="strong"><strong>alias</strong></span> if not within
<code class="literal">"…"</code> or <code class="literal">'…'</code>.
</p>
</li>
<li class="listitem">
<p>
The shell expands <span class="strong"><strong>tilde</strong></span> if not within
<code class="literal">"…"</code> or <code class="literal">'…'</code>.
</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
"<code class="literal">~</code>" → el directorio home del usuario actual
</p>
</li>
<li class="listitem">
<p>
"<code class="literal">~<usuario></code>" → el directorio home de
<code class="literal"><usuario></code>
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
The shell expands <span class="strong"><strong>parameter</strong></span> to its value
if not within <code class="literal">'…'</code>.
</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p><span class="strong"><strong>parameter</strong></span>:
"<code class="literal">$PARAMETER</code>" or "<code class="literal">${PARAMETER}</code>"
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
The shell expands <span class="strong"><strong>command substitution</strong></span> if
not within <code class="literal">'…'</code>.
</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
"<code class="literal">$( comando )</code>" → la salida de
"<code class="literal">comando</code>"
</p>
</li>
<li class="listitem">
<p>
"<code class="literal">` comando `</code>" → la salida de "<code class="literal">comando</code>"
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
The shell expands <span class="strong"><strong>pathname glob</strong></span> to
matching file names if not within <code class="literal">"…"</code> or
<code class="literal">'…'</code>.
</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p><code class="literal">*</code> → cualesquier caracteres
</p>
</li>
<li class="listitem">
<p><code class="literal">?</code> → un caracter
</p>
</li>
<li class="listitem">
<p><code class="literal">[…]</code> → cualquiera de los caracteres en
"<code class="literal">…</code>"
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
The shell looks up <span class="strong"><strong>command</strong></span> from the
following and execute it.
</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p><span class="strong"><strong>function</strong></span> definition
</p>
</li>
<li class="listitem">
<p><span class="strong"><strong>builtin</strong></span> command
</p>
</li>
<li class="listitem">
<p><span class="strong"><strong>executable file</strong></span> in
"<code class="literal">$PATH</code>"
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
The shell goes to the next line and repeats this process again from the top
of this sequence.
</p>
</li>
</ul>
</div>
<p>Las comillas simples no tienen efecto dentro de comillas dobles.</p>
<p>Executing "<code class="literal">set -x</code>" in the shell or invoking the shell
with "<code class="literal">-x</code>" option make the shell to print all of commands
executed. This is quite handy for debugging.</p>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_utility_programs_for_shell_script"/>12.1.6. Utility programs for shell script</h3>
</div>
</div>
</div>
<p>In order to make your shell program as portable as possible across Debian
systems, it is a good idea to limit utility programs to ones provided by
<span class="strong"><strong>essential</strong></span> packages.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
"<code class="literal">aptitude search ~E</code>" lista paquetes <span class="strong"><strong>esenciales</strong></span>.
</p>
</li>
<li class="listitem">
<p>
"<code class="literal">dpkg -L <paquete> | grep '/man/man.*/'</code>" lista
páginas 'man' para los comandos que ofrece
<code class="literal"><paquete></code>.
</p>
</li>
</ul>
</div>
<div class="table">
<a id="listofpackagescosforshellscripts"/>
<p class="title">
<strong>Tabla 12.8. List of packages containing small utility programs for shell scripts</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of packages containing small utility programs for shell scripts" 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">
paquete
</th>
<th style="text-align: left">
popularidad
</th>
<th style="text-align: left">
tamaño
</th>
<th style="text-align: left">
descripción
</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">
GNU core utilities
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/debianutils">
<code class="literal">debianutils</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=debianutils">V:934, I:999</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/d/debianutils.html">213</a>
</td>
<td style="text-align: left">
miscellaneous utilities specific to Debian
</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">
collection of more utilities from FreeBSD
</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">
basic utilities from 4.4BSD-Lite
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/moreutils">
<code class="literal">moreutils</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=moreutils">V:4, I:19</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/m/moreutils.html">201</a>
</td>
<td style="text-align: left">
additional Unix utilities
</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="[Sugerencia]" src="images/tip.png"/>
</td>
<th align="left">Sugerencia</th>
</tr>
<tr>
<td align="left" valign="top">
<p>Although <code class="literal">moreutils</code> may not exist ouside of Debian, it
offers interesting small programs. Most notable one is
<span class="citerefentry"><span class="refentrytitle">sponge</span>(8)</span>
which is quite useful when you wish to overwrite original file.</p>
</td>
</tr>
</table>
</div>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_shell_script_dialog"/>12.1.7. Shell script dialog</h3>
</div>
</div>
</div>
<p>The user interface of a simple shell program can be improved from dull
interaction by <code class="literal">echo</code> and <code class="literal">read</code> commands
to more interactive one by using one of the so-called dialog program etc.</p>
<div class="table">
<a id="listofuserinterfaceprograms"/>
<p class="title">
<strong>Tabla 12.9. List of user interface programs</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of user interface programs" 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">
paquete
</th>
<th style="text-align: left">
popularidad
</th>
<th style="text-align: left">
tamaño
</th>
<th style="text-align: left">
descripción
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/x11-utils">
<code class="literal">x11-utils</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=x11-utils">V:305, I:635</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/x/x11-utils.html">637</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">xmessage</span>(1)</span>:
display a message or query in a window (X)
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/whiptail">
<code class="literal">whiptail</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=whiptail">V:415, I:995</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/w/whiptail.html">68</a>
</td>
<td style="text-align: left">
displays user-friendly dialog boxes from shell scripts (newt)
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/dialog">
<code class="literal">dialog</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=dialog">V:29, I:151</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/d/dialog.html">1111</a>
</td>
<td style="text-align: left">
displays user-friendly dialog boxes from shell scripts (ncurses)
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/zenity">
<code class="literal">zenity</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=zenity">V:112, I:425</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/z/zenity.html">362</a>
</td>
<td style="text-align: left">
display graphical dialog boxes from shell scripts (gtk2.0)
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/ssft"> <code class="literal">ssft</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=ssft">V:0, I:0</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/s/ssft.html">129</a>
</td>
<td style="text-align: left">
Shell Scripts Frontend Tool (wrapper for zenity, kdialog, and dialog with
gettext)
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/gettext">
<code class="literal">gettext</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=gettext">V:53, I:367</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/g/gettext.html">7076</a>
</td>
<td style="text-align: left">
"<code class="literal">/usr/bin/gettext.sh</code>": translate message
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_shell_script_example_with_zenity"/>12.1.8. Shell script example with zenity</h3>
</div>
</div>
</div>
<p>Here is a simple script which creates ISO image with RS02 data supplemented
by
<span class="citerefentry"><span class="refentrytitle">dvdisaster</span>(1)</span>.</p>
<pre class="screen">#!/bin/sh -e
# gmkrs02 : Copyright (C) 2007 Osamu Aoki <osamu@debian.org>, Public Domain
#set -x
error_exit()
{
echo "$1" >&2
exit 1
}
# Initialize variables
DATA_ISO="$HOME/Desktop/iso-$$.img"
LABEL=$(date +%Y%m%d-%H%M%S-%Z)
if [ $# != 0 ] && [ -d "$1" ]; then
DATA_SRC="$1"
else
# Select directory for creating ISO image from folder on desktop
DATA_SRC=$(zenity --file-selection --directory \
--title="Select the directory tree root to create ISO image") \
|| error_exit "Exit on directory selection"
fi
# Check size of archive
xterm -T "Check size $DATA_SRC" -e du -s $DATA_SRC/*
SIZE=$(($(du -s $DATA_SRC | awk '{print $1}')/1024))
if [ $SIZE -le 520 ] ; then
zenity --info --title="Dvdisaster RS02" --width 640 --height 400 \
--text="The data size is good for CD backup:\\n $SIZE MB"
elif [ $SIZE -le 3500 ]; then
zenity --info --title="Dvdisaster RS02" --width 640 --height 400 \
--text="The data size is good for DVD backup :\\n $SIZE MB"
else
zenity --info --title="Dvdisaster RS02" --width 640 --height 400 \
--text="The data size is too big to backup : $SIZE MB"
error_exit "The data size is too big to backup :\\n $SIZE MB"
fi
# only xterm is sure to have working -e option
# Create raw ISO image
rm -f "$DATA_ISO" || true
xterm -T "genisoimage $DATA_ISO" \
-e genisoimage -r -J -V "$LABEL" -o "$DATA_ISO" "$DATA_SRC"
# Create RS02 supplemental redundancy
xterm -T "dvdisaster $DATA_ISO" -e dvdisaster -i "$DATA_ISO" -mRS02 -c
zenity --info --title="Dvdisaster RS02" --width 640 --height 400 \
--text="ISO/RS02 data ($SIZE MB) \\n created at: $DATA_ISO"
# EOF</pre>
<p>You may wish to create launcher on the desktop with command set something
like "<code class="literal">/usr/local/bin/gmkrs02 %d</code>".</p>
</div>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_make"/>12.2. Make</h2>
</div>
</div>
</div>
<p><a class="ulink" href="http://es.wikipedia.org/wiki/Make">Make</a> is a utility to maintain groups of
programs. Upon execution of
<span class="citerefentry"><span class="refentrytitle">make</span>(1)</span>,
<code class="literal">make</code> read the rule file, "<code class="literal">Makefile</code>",
and updates a target if it depends on prerequisite files that have been
modified since the target was last modified, or if the target does not
exist. The execution of these updates may occur concurrently.</p>
<p>The rule file syntax is the following.</p>
<pre class="screen">target: [ prerequisites ... ]
[TAB] command1
[TAB] -command2 # ignore errors
[TAB] @command3 # suppress echoing</pre>
<p>Here "<code class="literal">[TAB]</code>" is a TAB code. Each line is interpreted by
the shell after make variable substitution. Use "<code class="literal">\</code>" at
the end of a line to continue the script. Use "<code class="literal">$$</code>" to
enter "<code class="literal">$</code>" for environment values for a shell script.</p>
<p>Implicit rules for the target and prerequisites can be written, for example,
by the following.</p>
<pre class="screen">%.o: %.c header.h</pre>
<p>Here, the target contains the character "<code class="literal">%</code>" (exactly one
of them). The "<code class="literal">%</code>" can match any nonempty substring in the
actual target filenames. The prerequisites likewise use
"<code class="literal">%</code>" to show how their names relate to the actual target
name.</p>
<div class="table">
<a id="listofmakeautomaticvariables"/>
<p class="title">
<strong>Tabla 12.10. List of make automatic variables</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of make automatic variables" border="1">
<colgroup>
<col style="text-align: left"/>
<col style="text-align: left"/>
</colgroup>
<thead>
<tr>
<th style="text-align: left">
variable automática
</th>
<th style="text-align: left">
valor
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<code class="literal">$@</code>
</td>
<td style="text-align: left">
target
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">$<</code>
</td>
<td style="text-align: left">
first prerequisite
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">$?</code>
</td>
<td style="text-align: left">
all newer prerequisites
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">$^</code>
</td>
<td style="text-align: left">
all prerequisites
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">$*</code>
</td>
<td style="text-align: left">
"<code class="literal">%</code>" matched stem in the target pattern
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<div class="table">
<a id="listofmakevariableexpansions"/>
<p class="title">
<strong>Tabla 12.11. List of make variable expansions</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of make variable expansions" border="1">
<colgroup>
<col style="text-align: left"/>
<col style="text-align: left"/>
</colgroup>
<thead>
<tr>
<th style="text-align: left">
expansión variable
</th>
<th style="text-align: left">
descripción
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<code class="literal">foo1 := bar</code>
</td>
<td style="text-align: left">
expansión por única vez
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">foo2 = bar</code>
</td>
<td style="text-align: left">
expansión recursiva
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">foo3 += bar</code>
</td>
<td style="text-align: left">
anexar
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>Run "<code class="literal">make -p -f/dev/null</code>" to see automatic internal
rules.</p>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_c"/>12.3. C</h2>
</div>
</div>
</div>
<p>You can set up proper environment to compile programs written in the <a class="ulink" href="https://es.wikipedia.org/wiki/C_(lenguaje_de_programación)">C programming language</a> by the
following.</p>
<pre class="screen"># apt-get install glibc-doc manpages-dev libc6-dev gcc build-essential</pre>
<p>The <code class="literal">libc6-dev</code> package, i.e., GNU C Library, provides
<a class="ulink" href="https://es.wikipedia.org/wiki/Biblioteca_estándar_de_C">C standard library</a> which is
collection of header files and library routines used by the C programming
language.</p>
<p>See references for C as the following.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
"<code class="literal">info libc</code>" (C library function reference)
</p>
</li>
<li class="listitem">
<p><span class="citerefentry"><span class="refentrytitle">gcc</span>(1)</span>
y "<code class="literal">info gcc</code>"
</p>
</li>
<li class="listitem">
<p><span class="citerefentry"><span class="refentrytitle">each_C_library_function_name</span>(3)</span>
</p>
</li>
<li class="listitem">
<p>
Kernighan & Ritchie, "The C Programming Language", 2nd edition (Prentice
Hall)
</p>
</li>
</ul>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_simple_c_program_gcc"/>12.3.1. Programa sencillo en C (gcc)</h3>
</div>
</div>
</div>
<p>Se puede crear un ejecutable "<code class="literal">ejecutable_de_ejemplo</code>"
utilizando la biblioteca "<code class="literal">libm</code>" mediante este sencillo
ejemplo.</p>
<pre class="screen">$ cat > ejemplo.c << EOF
#include <stdio.h>
#include <math.h>
#include <string.h>
int main(int argc, char **argv, char **envp){
double x;
char y[11];
x=sqrt(argc+7.5);
strncpy(y, argv[0], 10); /* evita el desbordamiento */
y[10] = '\0'; /* asegura que la cadena finaliza con '\0' */
printf("%5i, %5.3f, %10s, %10s\n", argc, x, y, argv[1]);
return 0;
}
EOF
$ gcc -Wall -g -o ejecutable_de_ejemplo ejemplo..c -lm
$ ./ejecutable_de_ejemplo
1, 2.915, ./run_exam, (null)
$ ./run_example 1234567890qwerty
2, 3.082, ./run_exam, 1234567890qwerty</pre>
<p>Aquí, se necesita "<code class="literal">-lm</code>" para enlazar la biblioteca
"<code class="literal">/usr/lib/libm.so</code>" del paquete <code class="literal">libc6</code>
para utilizar la función
<span class="citerefentry"><span class="refentrytitle">sqrt</span>(3)</span>.
La biblioteca actual está ubicada en "<code class="literal">/lib/</code>" con el
nombre de archivo "<code class="literal">libm.so.6</code>", el cual es un enlace
simbólico a "<code class="literal">libm-2.7.so</code>".</p>
<p>Mire el último elemento de la salida. Tiene incluso más de 10 caracteres a
pesar de tener "<code class="literal">%10s</code>".</p>
<p>La utilización de operaciones de punteros sin comprobar los límites, como
ocurre con
<span class="citerefentry"><span class="refentrytitle">sprintf</span>(3)</span>
y
<span class="citerefentry"><span class="refentrytitle">strcpy</span>(3)</span>,
no se utilizan para evitar el desbordamiento del buffer que puede provocar
problemas desconocidos. En su lugar se utilizan
<span class="citerefentry"><span class="refentrytitle">snprintf</span>(3)</span>
y
<span class="citerefentry"><span class="refentrytitle">strncpy</span>(3)</span>.</p>
</div>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_debug"/>12.4. Depuración</h2>
</div>
</div>
</div>
<p>La depuración es una de las actividades más importantes de la
programación. Conocer como depurar un programa le convierte en un usuario de
Debian mejor que puede aportar informes de error relevantes.</p>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_basic_gdb_execution"/>12.4.1. Fundamentos de gdb</h3>
</div>
</div>
</div>
<p>El principal <a class="ulink" href="https://es.wikipedia.org/wiki/Depurador">depurador</a> en Debian es
<span class="citerefentry"><span class="refentrytitle">gdb</span>(1)</span>
el cual permite inspeccionar un programa mientras se ejecuta.</p>
<p>Instalemo <code class="literal">gdb</code> y otros programas relevantes com se
muestra.</p>
<pre class="screen"># apt-get install gdb gdb-doc build-essential devscripts</pre>
<p>Puede encontrar un buen tutorial de <code class="literal">gdb</code> en "<code class="literal">info
gdb</code>" y mucha más información <a class="ulink" href="http://www.unknownroad.com/rtfm/gdbtut/gdbtoc.html">a
través de Internet</a>. Aquí hay un ejemplo sencillo de la utilización
de
<span class="citerefentry"><span class="refentrytitle">gdb</span>(1)</span>
en un "<code class="literal">programa</code>" que ha sido compilado para producir
información de depuración con la opción "<code class="literal">-g</code>".</p>
<pre class="screen">$ gdb programa
(gdb) b 1 # pone un punto de ruptura en la línea 1
(gdb) run args # ejecuta el programa con args
(gdb) next # siguiente línea
...
(gdb) step # paso hacia adelante
...
(gdb) p parm # imprime el valor de parm
...
(gdb) p parm=12 # le asigna el valor de 12
...
(gdb) quit</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="[Sugerencia]" src="images/tip.png"/>
</td>
<th align="left">Sugerencia</th>
</tr>
<tr>
<td align="left" valign="top">
<p>Existen abreviaturas para la mayor parte de las órdenes de
<span class="citerefentry"><span class="refentrytitle">gdb</span>(1)</span>.
La expansión del tabulador funciona de la misma manera que en el intérprete
de órdenes.</p>
</td>
</tr>
</table>
</div>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_debugging_the_debian_package"/>12.4.2. Depurando un paquete Debian</h3>
</div>
</div>
</div>
<p>Por defecto, en un paquete normal, los binarios del sistema Debian deben
estar limpios por lo que la mayor parte de los símbolos del sistema son
eliminados. Para depurar un paquete Debian con
<span class="citerefentry"><span class="refentrytitle">gdb</span>(1)</span>,
se necesita la instalación de los paquetes <code class="literal">*-dbg</code>
(p. ej. <code class="literal">libc6-dbg</code> en el caso de la
<code class="literal">libc6</code>).</p>
<p>If a package to be debugged does not provide its <code class="literal">*-dbg</code>
package, you need to install it after rebuilding it by the following.</p>
<pre class="screen">$ mkdir /path/new ; cd /path/new
$ sudo apt-get update
$ sudo apt-get dist-upgrade
$ sudo apt-get install fakeroot devscripts build-essential
$ sudo apt-get build-dep source_package_name
$ apt-get source package_name
$ cd package_name*</pre>
<p>Fix bugs if needed.</p>
<p>Bump package version to one which does not collide with official Debian
versions, e.g. one appended with "<code class="literal">+debug1</code>" when
recompiling existing package version, or one appended with
"<code class="literal">~pre1</code>" when compiling unreleased package version by the
following.</p>
<pre class="screen">$ dch -i</pre>
<p>Compile and install packages with debug symbols by the following.</p>
<pre class="screen">$ export DEB_BUILD_OPTIONS=nostrip,noopt
$ debuild
$ cd ..
$ sudo debi package_name*.changes</pre>
<p>You need to check build scripts of the package and ensure to use
"<code class="literal">CFLAGS=-g -Wall</code>" for compiling binaries.</p>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_obtaining_backtrace"/>12.4.3. Obtaining backtrace</h3>
</div>
</div>
</div>
<p>When you encounter program crash, reporting bug report with cut-and-pasted
backtrace information is a good idea.</p>
<p>The backtrace can be obtained by the following steps.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
Run the program under
<span class="citerefentry"><span class="refentrytitle">gdb</span>(1)</span>.
</p>
</li>
<li class="listitem">
<p>
Reproduce crash.
</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
It causes you to be dropped back to the <code class="literal">gdb</code> prompt.
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
Type "<code class="literal">bt</code>" at the <code class="literal">gdb</code> prompt.
</p>
</li>
</ul>
</div>
<p>In case of program freeze, you can crash the program by pressing
<code class="literal">Ctrl-C</code> in the terminal running <code class="literal">gdb</code> to
obtain <code class="literal">gdb</code> prompt.</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="[Sugerencia]" src="images/tip.png"/>
</td>
<th align="left">Sugerencia</th>
</tr>
<tr>
<td align="left" valign="top">
<p>Often, you see a backtrace where one or more of the top lines are in
"<code class="literal">malloc()</code>" or "<code class="literal">g_malloc()</code>". When this
happens, chances are your backtrace isn't very useful. The easiest way to
find some useful information is to set the environment variable
"<code class="literal">$MALLOC_CHECK_</code>" to a value of 2
(<span class="citerefentry"><span class="refentrytitle">malloc</span>(3)</span>).
You can do this while running <code class="literal">gdb</code> by doing the following.</p>
</td>
</tr>
</table>
</div>
<pre class="screen"> $ MALLOC_CHECK_=2 gdb hello</pre>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_advanced_gdb_commands"/>12.4.4. Advanced gdb commands</h3>
</div>
</div>
</div>
<div class="table">
<a id="listofadvancedgdbcommands"/>
<p class="title">
<strong>Tabla 12.12. List of advanced gdb commands</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of advanced gdb commands" border="1">
<colgroup>
<col style="text-align: left"/>
<col style="text-align: left"/>
</colgroup>
<thead>
<tr>
<th style="text-align: left">
orden
</th>
<th style="text-align: left">
description for command objectives
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<code class="literal">(gdb) thread apply all bt</code>
</td>
<td style="text-align: left">
get a backtrace for all threads for multi-threaded program
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">(gdb) bt full</code>
</td>
<td style="text-align: left">
get parameters came on the stack of function calls
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">(gdb) thread apply all bt full</code>
</td>
<td style="text-align: left">
get a backtrace and parameters as the combination of the preceding options
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">(gdb) thread apply all bt full 10</code>
</td>
<td style="text-align: left">
get a backtrace and parameters for top 10 calls to cut off irrelevant output
</td>
</tr>
<tr>
<td style="text-align: left">
<code class="literal">(gdb) set logging on</code>
</td>
<td style="text-align: left">
write log of <code class="literal">gdb</code> output to a file (the default is
"<code class="literal">gdb.txt</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="_debugging_x_errors"/>12.4.5. Debugging X Errors</h3>
</div>
</div>
</div>
<p>If a GNOME program <code class="literal">preview1</code> has received an X error, you
should see a message as follows.</p>
<pre class="screen">The program 'preview1' received an X Window System error.</pre>
<p>If this is the case, you can try running the program with
"<code class="literal">--sync</code>", and break on the
"<code class="literal">gdk_x_error</code>" function in order to obtain a backtrace.</p>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_check_dependency_on_libraries"/>12.4.6. Check dependency on libraries</h3>
</div>
</div>
</div>
<p>Use
<span class="citerefentry"><span class="refentrytitle">ldd</span>(1)</span>
to find out a program's dependency on libraries by the followings.</p>
<pre class="screen">$ ldd /bin/ls
librt.so.1 => /lib/librt.so.1 (0x4001e000)
libc.so.6 => /lib/libc.so.6 (0x40030000)
libpthread.so.0 => /lib/libpthread.so.0 (0x40153000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x40000000)</pre>
<p>For
<span class="citerefentry"><span class="refentrytitle">ls</span>(1)</span>
to work in a `chroot`ed environment, the above libraries must be available
in your `chroot`ed environment.</p>
<p>See <a class="xref" href="ch09.es.html#_tracing_program_activities" title="9.3.6. Trazando la actividad de un programa">Sección 9.3.6, “Trazando la actividad de un programa”</a>.</p>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_memory_leak_detection_tools"/>12.4.7. Memory leak detection tools</h3>
</div>
</div>
</div>
<p>There are several memory leak detection tools available in Debian.</p>
<div class="table">
<a id="listofmemoryleakdetectiontools"/>
<p class="title">
<strong>Tabla 12.13. List of memory leak detection tools</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of memory leak detection 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">
paquete
</th>
<th style="text-align: left">
popularidad
</th>
<th style="text-align: left">
tamaño
</th>
<th style="text-align: left">
descripción
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/libc6-dev">
<code class="literal">libc6-dev</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=libc6-dev">V:269, I:615</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/libc/libc6-dev.html">15628</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">mtrace</span>(1)</span>:
malloc debugging functionality in glibc
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/valgrind">
<code class="literal">valgrind</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=valgrind">V:8, I:56</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/v/valgrind.html">70463</a>
</td>
<td style="text-align: left">
memory debugger and profiler
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/kmtrace">
<code class="literal">kmtrace</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=kmtrace">V:1, I:18</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/k/kmtrace.html">351</a>
</td>
<td style="text-align: left">
KDE memory leak tracer using glibc's
<span class="citerefentry"><span class="refentrytitle">mtrace</span>(1)</span>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/alleyoop">
<code class="literal">alleyoop</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=alleyoop">V:0, I:1</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/a/alleyoop.html">655</a>
</td>
<td style="text-align: left">
GNOME front-end to the Valgrind memory checker
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/electric-fence">
<code class="literal">electric-fence</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=electric-fence">V:0, I:6</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/e/electric-fence.html">70</a>
</td>
<td style="text-align: left"><span class="citerefentry"><span class="refentrytitle">malloc</span>(3)</span>
debugger
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/leaktracer">
<code class="literal">leaktracer</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=leaktracer">V:0, I:2</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/l/leaktracer.html">56</a>
</td>
<td style="text-align: left">
memory-leak tracer for C++ programs
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/libdmalloc5">
<code class="literal">libdmalloc5</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=libdmalloc5">V:0, I:3</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/libd/libdmalloc5.html">360</a>
</td>
<td style="text-align: left">
debug memory allocation library
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_static_code_analysis_tools"/>12.4.8. Static code analysis tools</h3>
</div>
</div>
</div>
<p>There are <a class="ulink" href="http://es.wikipedia.org/wiki/Lint">lint</a> like tools for <a class="ulink" href="https://es.wikipedia.org/wiki/Anexo:Herramientas_para_el_análisis_estático_de_software">static code analysis</a>.</p>
<div class="table">
<a id="listoftoolsforstaticcodeanalysis"/>
<p class="title">
<strong>Tabla 12.14. List of tools for static code analysis</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of tools for static code 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">
paquete
</th>
<th style="text-align: left">
popularidad
</th>
<th style="text-align: left">
tamaño
</th>
<th style="text-align: left">
descripción
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/splint">
<code class="literal">splint</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=splint">V:0, I:5</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/s/splint.html">1889</a>
</td>
<td style="text-align: left">
tool for statically checking C programs for bugs
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/flawfinder">
<code class="literal">flawfinder</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=flawfinder">V:0, I:1</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/f/flawfinder.html">175</a>
</td>
<td style="text-align: left">
tool to examine C/C++ source code and looks for security weaknesses
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/perl"> <code class="literal">perl</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=perl">V:610, I:996</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/p/perl.html">651</a>
</td>
<td style="text-align: left">
interpreter with internal static code checker:
<span class="citerefentry"><span class="refentrytitle">B::Lint</span>(3perl)</span>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/pylint">
<code class="literal">pylint</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=pylint">V:6, I:15</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/p/pylint.html">945</a>
</td>
<td style="text-align: left">
Python code static checker
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/weblint-perl">
<code class="literal">weblint-perl</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=weblint-perl">V:0, I:2</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/w/weblint-perl.html">34</a>
</td>
<td style="text-align: left">
syntax and minimal style checker for HTML
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/linklint">
<code class="literal">linklint</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=linklint">V:0, I:1</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/l/linklint.html">343</a>
</td>
<td style="text-align: left">
fast link checker and web site maintenance tool
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/libxml2-utils">
<code class="literal">libxml2-utils</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=libxml2-utils">V:24, I:318</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/libx/libxml2-utils.html">177</a>
</td>
<td style="text-align: left">
utilities with
<span class="citerefentry"><span class="refentrytitle">xmllint</span>(1)</span>
to validate XML files
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_disassemble_binary"/>12.4.9. Disassemble binary</h3>
</div>
</div>
</div>
<p>You can disassemble binary code with
<span class="citerefentry"><span class="refentrytitle">objdump</span>(1)</span>
by the following.</p>
<pre class="screen">$ objdump -m i386 -b binary -D /usr/lib/grub/x86_64-pc/stage1</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="[Nota]" src="images/note.png"/>
</td>
<th align="left">Nota</th>
</tr>
<tr>
<td align="left" valign="top">
<p><span class="citerefentry"><span class="refentrytitle">gdb</span>(1)</span>
may be used to disassemble code interactively.</p>
</td>
</tr>
</table>
</div>
</div>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_flex_a_better_lex"/>12.5. Flex — a better Lex</h2>
</div>
</div>
</div>
<p><a class="ulink" href="http://en.wikipedia.org/wiki/Flex_lexical_analyser">Flex</a> is a <a class="ulink" href="http://es.wikipedia.org/wiki/Lex_(informática)">Lex</a>-compatible fast <a class="ulink" href="https://es.wikipedia.org/wiki/Compilador#Análisis_léxico">lexical analyzer</a> generator.</p>
<p>Tutorial for
<span class="citerefentry"><span class="refentrytitle">flex</span>(1)</span>
can be found in "<code class="literal">info flex</code>".</p>
<p>You need to provide your own "<code class="literal">main()</code>" and
"<code class="literal">yywrap()</code>". Otherwise, your flex program should look
like this to compile without a library. This is because that
"<code class="literal">yywrap</code>" is a macro and "<code class="literal">%option main</code>"
turns on "<code class="literal">%option noyywrap</code>" implicitly.</p>
<pre class="screen">%option main
%%
.|\n ECHO ;
%%</pre>
<p>Alternatively, you may compile with the "<code class="literal">-lfl</code>" linker
option at the end of your
<span class="citerefentry"><span class="refentrytitle">cc</span>(1)</span>
command line (like AT&T-Lex with "<code class="literal">-ll</code>"). No
"<code class="literal">%option</code>" is needed in this case.</p>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_bison_a_better_yacc"/>12.6. Bison — a better Yacc</h2>
</div>
</div>
</div>
<p>Several packages provide a <a class="ulink" href="http://es.wikipedia.org/wiki/Yacc">Yacc</a>-compatible
lookahead <a class="ulink" href="http://es.wikipedia.org/wiki/Analizador_sintáctico_LR">LR parser</a> or <a class="ulink" href="http://en.wikipedia.org/wiki/LALR_parser">LALR parser</a> generator in Debian.</p>
<div class="table">
<a id="listofyacccompatparsergenerators"/>
<p class="title">
<strong>Tabla 12.15. List of Yacc-compatible LALR parser generators</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of Yacc-compatible LALR parser generators" 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">
paquete
</th>
<th style="text-align: left">
popularidad
</th>
<th style="text-align: left">
tamaño
</th>
<th style="text-align: left">
descripción
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/bison"> <code class="literal">bison</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=bison">V:10, I:113</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/b/bison.html">2061</a>
</td>
<td style="text-align: left">
<a class="ulink" href="https://es.wikipedia.org/wiki/GNU_Bison">GNU LALR parser generator</a>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/byacc"> <code class="literal">byacc</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=byacc">V:0, I:7</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/b/byacc.html">160</a>
</td>
<td style="text-align: left">
Berkeley LALR parser generator
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/btyacc">
<code class="literal">btyacc</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=btyacc">V:0, I:0</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/b/btyacc.html">207</a>
</td>
<td style="text-align: left">
backtracking parser generator based on <code class="literal">byacc</code>
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
<p>Tutorial for
<span class="citerefentry"><span class="refentrytitle">bison</span>(1)</span>
can be found in "<code class="literal">info bison</code>".</p>
<p>You need to provide your own "<code class="literal">main()</code>" and
"<code class="literal">yyerror()</code>". "<code class="literal">main()</code>" calls
"<code class="literal">yyparse()</code>" which calls "<code class="literal">yylex()</code>",
usually created with Flex.</p>
<pre class="screen">%%
%%</pre>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_autoconf"/>12.7. Autoconf</h2>
</div>
</div>
</div>
<p><a class="ulink" href="https://es.wikipedia.org/wiki/Autoconf">Autoconf</a> is a tool for producing shell
scripts that automatically configure software source code packages to adapt
to many kinds of Unix-like systems using the entire GNU build system.</p>
<p><span class="citerefentry"><span class="refentrytitle">autoconf</span>(1)</span>
produces the configuration script
"<code class="literal">configure</code>". "<code class="literal">configure</code>" automatically
creates a customized "<code class="literal">Makefile</code>" using the
"<code class="literal">Makefile.in</code>" template.</p>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_compile_and_install_a_program"/>12.7.1. Compile and install a program</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="[Aviso]" src="images/warning.png"/>
</td>
<th align="left">Aviso</th>
</tr>
<tr>
<td align="left" valign="top">
<p>Do not overwrite system files with your compiled programs when installing
them.</p>
</td>
</tr>
</table>
</div>
<p>Debian does not touch files in "<code class="literal">/usr/local/</code>" or
"<code class="literal">/opt</code>". So if you compile a program from source, install
it into "<code class="literal">/usr/local/</code>" so it does not interfere with
Debian.</p>
<pre class="screen">$ cd src
$ ./configure --prefix=/usr/local
$ make
$ make install # this puts the files in the system</pre>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h3 class="title"><a id="_uninstall_program"/>12.7.2. Uninstall program</h3>
</div>
</div>
</div>
<p>If you have the original source and if it uses
<span class="citerefentry"><span class="refentrytitle">autoconf</span>(1)</span>/<span class="citerefentry"><span class="refentrytitle">automake</span>(1)</span>
and if you can remember how you configured it, execute as follows to
uninstall the program.</p>
<pre class="screen">$ ./configure "all-of-the-options-you-gave-it"
# make uninstall</pre>
<p>Alternatively, if you are absolutely sure that the install process puts
files only under "<code class="literal">/usr/local/</code>" and there is nothing
important there, you can erase all its contents by the following.</p>
<pre class="screen"># find /usr/local -type f -print0 | xargs -0 rm -f</pre>
<p>If you are not sure where files are installed, you should consider using
<span class="citerefentry"><span class="refentrytitle">checkinstall</span>(8)</span>
from the <code class="literal">checkinstall</code> package, which provides a clean
path for the uninstall. It now supports to create a Debian package with
"<code class="literal">-D</code>" option.</p>
</div>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_perl_short_script_madness"/>12.8. Perl short script madness</h2>
</div>
</div>
</div>
<p>Although any <a class="ulink" href="https://es.wikipedia.org/wiki/AWK">AWK</a> scripts can be automatically
rewritten in <a class="ulink" href="http://es.wikipedia.org/wiki/Perl">Perl</a> using
<span class="citerefentry"><span class="refentrytitle">a2p</span>(1)</span>,
one-liner AWK scripts are best converted to one-liner Perl scripts manually.</p>
<p>Let's think following AWK script snippet.</p>
<pre class="screen">awk '($2=="1957") { print $3 }' |</pre>
<p>This is equivalent to any one of the following lines.</p>
<pre class="screen">perl -ne '@f=split; if ($f[1] eq "1957") { print "$f[2]\n"}' |</pre>
<pre class="screen">perl -ne 'if ((@f=split)[1] eq "1957") { print "$f[2]\n"}' |</pre>
<pre class="screen">perl -ne '@f=split; print $f[2] if ( $f[1]==1957 )' |</pre>
<pre class="screen">perl -lane 'print $F[2] if $F[1] eq "1957"' |</pre>
<pre class="screen">perl -lane 'print$F[2]if$F[1]eq+1957' |</pre>
<p>The last one is a riddle. It took advantage of following Perl features.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
The whitespace is optional.
</p>
</li>
<li class="listitem">
<p>
The automatic conversion exists from number to the string.
</p>
</li>
</ul>
</div>
<p>See
<span class="citerefentry"><span class="refentrytitle">perlrun</span>(1)</span>
for the command-line options. For more crazy Perl scripts, <a class="ulink" href="http://perlgolf.sourceforge.net">Perl Golf</a> may be interesting.</p>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_web"/>12.9. Web</h2>
</div>
</div>
</div>
<p>Basic interactive dynamic web pages can be made as follows.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
Queries are presented to the browser user using <a class="ulink" href="https://es.wikipedia.org/wiki/HTML">HTML</a> forms.
</p>
</li>
<li class="listitem">
<p>
Filling and clicking on the form entries sends one of the following <a class="ulink" href="http://es.wikipedia.org/wiki/Localizador_Uniforme_de_Recursos">URL</a> string with encoded parameters from the browser to
the web server.
</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p>
"<code class="literal">http://www.foo.dom/cgi-bin/program.pl?VAR1=VAL1&VAR2=VAL2&VAR3=VAL3</code>"
</p>
</li>
<li class="listitem">
<p>
"<code class="literal">http://www.foo.dom/cgi-bin/program.py?VAR1=VAL1&VAR2=VAL2&VAR3=VAL3</code>"
</p>
</li>
<li class="listitem">
<p>
"<code class="literal">http://www.foo.dom/program.php?VAR1=VAL1&VAR2=VAL2&VAR3=VAL3</code>"
</p>
</li>
</ul>
</div>
</li>
<li class="listitem">
<p>
"<code class="literal">%nn</code>" in URL is replaced with a character with
hexadecimal <code class="literal">nn</code> value.
</p>
</li>
<li class="listitem">
<p>
The environment variable is set as: "<code class="literal">QUERY_STRING="VAR1=VAL1
VAR2=VAL2 VAR3=VAL3"</code>".
</p>
</li>
<li class="listitem">
<p><a class="ulink" href="https://es.wikipedia.org/wiki/Interfaz_de_entrada_común">CGI</a> program (any one of
"<code class="literal">program.*</code>") on the web server executes itself with the
environment variable "<code class="literal">$QUERY_STRING</code>".
</p>
</li>
<li class="listitem">
<p><code class="literal">stdout</code> of CGI program is sent to the web browser and is
presented as an interactive dynamic web page.
</p>
</li>
</ul>
</div>
<p>For security reasons it is better not to hand craft new hacks for parsing
CGI parameters. There are established modules for them in Perl and Python.
<a class="ulink" href="http://es.wikipedia.org/wiki/PHP">PHP</a> comes with these functionalities. When
client data storage is needed, <a class="ulink" href="https://es.wikipedia.org/wiki/Cookie_(informática)">HTTP
cookies</a> are used. When client side data processing is needed,
<a class="ulink" href="https://es.wikipedia.org/wiki/JavaScript">Javascript</a> is frequently used.</p>
<p>For more, see the <a class="ulink" href="https://es.wikipedia.org/wiki/Interfaz_de_entrada_común">Common Gateway
Interface</a>, <a class="ulink" href="https://es.wikipedia.org/wiki/Apache_Software_Foundation">The Apache
Software Foundation</a>, and <a class="ulink" href="https://es.wikipedia.org/wiki/JavaScript">JavaScript</a>.</p>
<p>Searching "CGI tutorial" on Google by typing encoded URL <a class="ulink" href="http://www.google.com/search?hl=en&ie=UTF-8&q=CGI+tutorial">http://www.google.com/search?hl=en&ie=UTF-8&q=CGI+tutorial</a>
directly to the browser address is a good way to see the CGI script in
action on the Google server.</p>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_the_source_code_translation"/>12.10. The source code translation</h2>
</div>
</div>
</div>
<p>There are programs to convert source codes.</p>
<div class="table">
<a id="listofsourcecodetranslationtools"/>
<p class="title">
<strong>Tabla 12.16. List of source code translation tools</strong>
</p>
<div class="table-contents">
<table class="table" summary="List of source code translation tools" 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">
paquete
</th>
<th style="text-align: left">
popularidad
</th>
<th style="text-align: left">
tamaño
</th>
<th style="text-align: left">
palabra clave
</th>
<th style="text-align: left">
descripción
</th>
</tr>
</thead>
<tbody>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/perl"> <code class="literal">perl</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=perl">V:610, I:996</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/p/perl.html">651</a>
</td>
<td style="text-align: left">
AWK→PERL
</td>
<td style="text-align: left">
convert source codes from AWK to PERL:
<span class="citerefentry"><span class="refentrytitle">a2p</span>(1)</span>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/f2c"> <code class="literal">f2c</code>
</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=f2c">V:0, I:7</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/f/f2c.html">433</a>
</td>
<td style="text-align: left">
FORTRAN→C
</td>
<td style="text-align: left">
convert source codes from FORTRAN 77 to C/C++:
<span class="citerefentry"><span class="refentrytitle">f2c</span>(1)</span>
</td>
</tr>
<tr>
<td style="text-align: left">
<a class="ulink" href="http://packages.debian.org/sid/intel2gas">
<code class="literal">intel2gas</code> </a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://qa.debian.org/popcon.php?package=intel2gas">V:0, I:0</a>
</td>
<td style="text-align: left">
<a class="ulink" href="http://packages.qa.debian.org/i/intel2gas.html">174</a>
</td>
<td style="text-align: left">
intel→gas
</td>
<td style="text-align: left">
converter from NASM (Intel format) to the GNU Assembler (GAS)
</td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="table-break"/>
</div>
<div class="section">
<div class="titlepage">
<div>
<div>
<h2 class="title"><a id="_making_debian_package"/>12.11. Making Debian package</h2>
</div>
</div>
</div>
<p>If you want to make a Debian package, read followings.</p>
<div class="itemizedlist">
<ul class="itemizedlist">
<li class="listitem">
<p><a class="xref" href="ch02.es.html" title="Capítulo 2. Gestión de paquetes Debian">Capítulo 2, <em>Gestión de paquetes Debian</em></a> to understand the basic package
system
</p>
</li>
<li class="listitem">
<p><a class="xref" href="ch02.es.html#_porting_a_package_to_the_stable_system" title="2.7.13. Portar un paquete a un sistema estable">Sección 2.7.13, “Portar un paquete a un sistema estable”</a> to understand
basic porting process
</p>
</li>
<li class="listitem">
<p><a class="xref" href="ch09.es.html#_chroot_system" title="9.10.4. Sistemas chroot">Sección 9.10.4, “Sistemas chroot”</a> to understand basic chroot techniques
</p>
</li>
<li class="listitem">
<p><span class="citerefentry"><span class="refentrytitle">debuild</span>(1)</span>,
<span class="citerefentry"><span class="refentrytitle">pbuilder</span>(1)</span>
and
<span class="citerefentry"><span class="refentrytitle">pdebuild</span>(1)</span>
</p>
</li>
<li class="listitem">
<p><a class="xref" href="ch12.es.html#_debugging_the_debian_package" title="12.4.2. Depurando un paquete Debian">Sección 12.4.2, “Depurando un paquete Debian”</a> for recompiling for
debugging
</p>
</li>
<li class="listitem">
<p><a class="ulink" href="https://www.debian.org/doc/devel-manuals#maint-guide">Debian New Maintainers'
Guide</a> as tutorial (the <code class="literal">maint-guide</code> package)
</p>
</li>
<li class="listitem">
<p><a class="ulink" href="https://www.debian.org/doc/manuals/developers-reference/">Debian Developer's
Reference</a> (the <code class="literal">developers-reference</code> package)
</p>
</li>
<li class="listitem">
<p><a class="ulink" href="https://www.debian.org/doc/devel-manuals.es.html#policy">Debian Policy Manual</a> (the
<code class="literal">debian-policy</code> package)
</p>
</li>
<li class="listitem">
<p><a class="ulink" href="http://www.debian.org/doc/manuals/debmake-doc/">Guide for Debian
Maintainers</a> (the <code class="literal">debmake-doc</code> package)
</p>
</li>
</ul>
</div>
<p>There are packages such as <code class="literal">debmake</code>,
<code class="literal">dh-make</code>, <code class="literal">dh-make-perl</code>, etc., which
help packaging.</p>
</div>
</div>
<div class="navfooter">
<hr/>
<table width="100%" summary="Navigation footer">
<tr>
<td align="left"><a accesskey="p" href="ch11.es.html"><img src="images/prev.png" alt="Anterior"/></a> </td>
<td align="center"> </td>
<td align="right"> <a accesskey="n" href="apa.es.html"><img src="images/next.png" alt="Siguiente"/></a></td>
</tr>
<tr>
<td align="left" valign="top">Capítulo 11. Conversión de datos </td>
<td align="center">
<a accesskey="h" href="index.es.html">
<img src="images/home.png" alt="Inicio"/>
</a>
</td>
<td align="right" valign="top"> Apéndice A. Appendix</td>
</tr>
</table>
</div>
</body>
</html>
|