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<title>The Debian GNU/Linux FAQ - Customizing your installation of Debian GNU/Linux</title>

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<link href="ch-basic_defs.en.html" rel="chapter" title="1 Definitions and overview">
<link href="ch-getting.en.html" rel="chapter" title="2 Getting and installing Debian GNU/Linux">
<link href="ch-choosing.en.html" rel="chapter" title="3 Choosing a Debian distribution">
<link href="ch-compat.en.html" rel="chapter" title="4 Compatibility issues">
<link href="ch-software.en.html" rel="chapter" title="5 Software available in the Debian system">
<link href="ch-ftparchives.en.html" rel="chapter" title="6 The Debian FTP archives">
<link href="ch-pkg_basics.en.html" rel="chapter" title="7 Basics of the Debian package management system">
<link href="ch-pkgtools.en.html" rel="chapter" title="8 The Debian package management tools">
<link href="ch-uptodate.en.html" rel="chapter" title="9 Keeping your Debian system up-to-date">
<link href="ch-kernel.en.html" rel="chapter" title="10 Debian and the kernel">
<link href="ch-customizing.en.html" rel="chapter" title="11 Customizing your installation of Debian GNU/Linux">
<link href="ch-support.en.html" rel="chapter" title="12 Getting support for Debian GNU/Linux">
<link href="ch-contributing.en.html" rel="chapter" title="13 Contributing to the Debian Project">
<link href="ch-redistrib.en.html" rel="chapter" title="14 Redistributing Debian GNU/Linux in a commercial product">
<link href="ch-nexttime.en.html" rel="chapter" title="15 Changes expected in the next major release of Debian">
<link href="ch-faqinfo.en.html" rel="chapter" title="16 General information about the FAQ">
<link href="ch-basic_defs.en.html#s-whatisfaq" rel="section" title="1.1 What is this FAQ?">
<link href="ch-basic_defs.en.html#s-whatisdebian" rel="section" title="1.2 What is Debian GNU/Linux?">
<link href="ch-basic_defs.en.html#s-linux" rel="section" title="1.3 OK, now I know what Debian is... what is Linux?!">
<link href="ch-basic_defs.en.html#s-non-linux" rel="section" title="1.4 Does Debian just do GNU/Linux?">
<link href="ch-basic_defs.en.html#s-difference" rel="section" title="1.5 What is the difference between Debian GNU/Linux and other Linux distributions? Why should I choose Debian over some other distribution?">
<link href="ch-basic_defs.en.html#s-gnu" rel="section" title="1.6 How does the Debian project fit in or compare with the Free Software Foundation's GNU project?">
<link href="ch-basic_defs.en.html#s-pronunciation" rel="section" title="1.7 How does one pronounce Debian and what does this word mean?">
<link href="ch-getting.en.html#s-version" rel="section" title="2.1 What is the latest version of Debian?">
<link href="ch-getting.en.html#s-updatestable" rel="section" title="2.2 Are there package upgrades in `stable'?">
<link href="ch-getting.en.html#s-boot-floppies" rel="section" title="2.3 Where/how can I get the Debian installation disks?">
<link href="ch-getting.en.html#s-cdrom" rel="section" title="2.4 How do I install the Debian from CD-ROMs?">
<link href="ch-getting.en.html#s-cdimage-symlinks" rel="section" title="2.5 Why does the official stable released CD-ROM contain symlinks for `frozen' and `unstable'? I thought this CD contains just `stable'!">
<link href="ch-getting.en.html#s-remoteinstall" rel="section" title="2.6 Can I get and install Debian directly from a remote Internet site?">
<link href="ch-getting.en.html#s-alternativebootinstaller" rel="section" title="2.7 Are there any alternative strategies for booting the system installer?">
<link href="ch-choosing.en.html#s3.1" rel="section" title="3.1 Which Debian distribution (stable/testing/unstable) is better for me?">
<link href="ch-choosing.en.html#s3.2" rel="section" title="3.2 But what about Knoppix, Linex, Ubuntu, and others?">
<link href="ch-compat.en.html#s-arches" rel="section" title="4.1 On what hardware architectures/systems does Debian GNU/Linux run?">
<link href="ch-compat.en.html#s-otherdistribs" rel="section" title="4.2 How compatible is Debian with other distributions of Linux?">
<link href="ch-compat.en.html#s-otherunices" rel="section" title="4.3 How source code compatible is Debian with other Unix systems?">
<link href="ch-compat.en.html#s-otherpackages" rel="section" title="4.4 Can I use Debian packages (&quot;.deb&quot; files) on my Red Hat/Slackware/... Linux system? Can I use Red Hat packages (&quot;.rpm&quot; files) on my Debian GNU/Linux system?">
<link href="ch-compat.en.html#s-non-debian-programs" rel="section" title="4.5 How should I install a non-Debian program?">
<link href="ch-compat.en.html#s-termcap" rel="section" title="4.6 Why can't I compile programs that require libtermcap?">
<link href="ch-compat.en.html#s-accelx" rel="section" title="4.7 Why can't I install AccelX?">
<link href="ch-compat.en.html#s-motifnls" rel="section" title="4.8 Why do my old XFree 2.1 Motif applications crash?">
<link href="ch-software.en.html#s-apps" rel="section" title="5.1 What types of applications and development software are available for Debian GNU/Linux?">
<link href="ch-software.en.html#s-softwareauthors" rel="section" title="5.2 Who wrote all that software?">
<link href="ch-software.en.html#s-pkglist" rel="section" title="5.3 How can I get a current list of programs that have been packaged for Debian?">
<link href="ch-software.en.html#s-buildenv" rel="section" title="5.4 How can I install a developer's environment to build packages?">
<link href="ch-software.en.html#s-missing" rel="section" title="5.5 What is missing from Debian GNU/Linux?">
<link href="ch-software.en.html#s-no-devs" rel="section" title="5.6 Why do I get &quot;ld: cannot find -lfoo&quot; messages when compiling programs? Why aren't there any libfoo.so files in Debian library packages?">
<link href="ch-software.en.html#s-java" rel="section" title="5.7 (How) Does Debian support Java?">
<link href="ch-software.en.html#s-isitdebian" rel="section" title="5.8 How can I check that I am using a Debian system, and what version is it?">
<link href="ch-software.en.html#s-nonenglish" rel="section" title="5.9 How does Debian support non-English languages?">
<link href="ch-software.en.html#s-pine" rel="section" title="5.10 Where is pine?">
<link href="ch-software.en.html#s-qmail" rel="section" title="5.11 Where is qmail/ezmlm/djbdns?">
<link href="ch-software.en.html#s-flash" rel="section" title="5.12 Where is a player for Flash (SWF)?">
<link href="ch-software.en.html#s-googleearth" rel="section" title="5.13 Where is Google Earth?">
<link href="ch-software.en.html#s-voip" rel="section" title="5.14 Where is VoIP software?">
<link href="ch-software.en.html#s-nonfreewireless" rel="section" title="5.15 I have a wireless network card which doesn't work with Linux. What should I do?">
<link href="ch-ftparchives.en.html#s-dists" rel="section" title="6.1 How many Debian distributions are there?">
<link href="ch-ftparchives.en.html#s-codenames" rel="section" title="6.2 What are all those names like etch, lenny, etc.?">
<link href="ch-ftparchives.en.html#s-sid" rel="section" title="6.3 What about &quot;sid&quot;?">
<link href="ch-ftparchives.en.html#s-stable" rel="section" title="6.4 What does the stable directory contain?">
<link href="ch-ftparchives.en.html#s-testing" rel="section" title="6.5 What does the testing distribution contain?">
<link href="ch-ftparchives.en.html#s-unstable" rel="section" title="6.6 What does the unstable distribution contain?">
<link href="ch-ftparchives.en.html#s-dirtree" rel="section" title="6.7 What are all those directories at the Debian FTP archives?">
<link href="ch-ftparchives.en.html#s-archsections" rel="section" title="6.8 What are all those directories inside dists/stable/main?">
<link href="ch-ftparchives.en.html#s-source" rel="section" title="6.9 Where is the source code?">
<link href="ch-ftparchives.en.html#s-pools" rel="section" title="6.10 What's in the pool directory?">
<link href="ch-ftparchives.en.html#s-incoming" rel="section" title="6.11 What is &quot;incoming&quot;?">
<link href="ch-ftparchives.en.html#s-ownrepository" rel="section" title="6.12 How do I set up my own apt-able repository?">
<link href="ch-pkg_basics.en.html#s-package" rel="section" title="7.1 What is a Debian package?">
<link href="ch-pkg_basics.en.html#s-deb-format" rel="section" title="7.2 What is the format of a Debian binary package?">
<link href="ch-pkg_basics.en.html#s-pkgname" rel="section" title="7.3 Why are Debian package file names so long?">
<link href="ch-pkg_basics.en.html#s-controlfile" rel="section" title="7.4 What is a Debian control file?">
<link href="ch-pkg_basics.en.html#s-conffile" rel="section" title="7.5 What is a Debian conffile?">
<link href="ch-pkg_basics.en.html#s-maintscripts" rel="section" title="7.6 What is a Debian preinst, postinst, prerm, and postrm script?">
<link href="ch-pkg_basics.en.html#s-priority" rel="section" title="7.7 What is an Essential, Required, Important, Standard, Optional, or Extra package?">
<link href="ch-pkg_basics.en.html#s-virtual" rel="section" title="7.8 What is a Virtual Package?">
<link href="ch-pkg_basics.en.html#s-depends" rel="section" title="7.9 What is meant by saying that a package Depends, Recommends, Suggests, Conflicts, Replaces, Breaks or Provides another package?">
<link href="ch-pkg_basics.en.html#s-pre-depends" rel="section" title="7.10 What is meant by Pre-Depends?">
<link href="ch-pkg_basics.en.html#s-pkgstatus" rel="section" title="7.11 What is meant by unknown, install, remove, purge and hold in the package status?">
<link href="ch-pkg_basics.en.html#s-puttingonhold" rel="section" title="7.12 How do I put a package on hold?">
<link href="ch-pkg_basics.en.html#s-sourcepkgs" rel="section" title="7.13 How do I install a source package?">
<link href="ch-pkg_basics.en.html#s-sourcebuild" rel="section" title="7.14 How do I build binary packages from a source package?">
<link href="ch-pkg_basics.en.html#s-creatingdebs" rel="section" title="7.15 How do I create Debian packages myself?">
<link href="ch-pkgtools.en.html#s-pkgprogs" rel="section" title="8.1 What programs does Debian provide for managing its packages?">
<link href="ch-pkgtools.en.html#s-updaterunning" rel="section" title="8.2 Debian claims to be able to update a running program; how is this accomplished?">
<link href="ch-pkgtools.en.html#s-whatpackages" rel="section" title="8.3 How can I tell what packages are already installed on a Debian system?">
<link href="ch-pkgtools.en.html#s-listfiles" rel="section" title="8.4 How to display the files of a package installed?">
<link href="ch-pkgtools.en.html#s-filesearch" rel="section" title="8.5 How can I find out what package produced a particular file?">
<link href="ch-pkgtools.en.html#s-datapackages" rel="section" title="8.6 Why doesn't get `foo-data' removed when I uninstall `foo'? How do I make sure old unused library-packages get purged?">
<link href="ch-uptodate.en.html#s-howtocurrent" rel="section" title="9.1 How can I keep my Debian system current?">
<link href="ch-uptodate.en.html#s-upgradesingle" rel="section" title="9.2 Must I go into single user mode in order to upgrade a package?">
<link href="ch-uptodate.en.html#s-savedebs" rel="section" title="9.3 Do I have to keep all those .deb archive files on my disk?">
<link href="ch-uptodate.en.html#s-keepingalog" rel="section" title="9.4 How can I keep a log of the packages I added to the system? I'd like to know when which package upgrades and removals have occured!">
<link href="ch-uptodate.en.html#s-autoupdate" rel="section" title="9.5 Can I automatically update the system?">
<link href="ch-uptodate.en.html#s-aptproxy" rel="section" title="9.6 I have several machines how can I download the updates only one time?">
<link href="ch-kernel.en.html#s-non-debian-kernel" rel="section" title="10.1 Can I install and compile a kernel without some Debian-specific tweaking?">
<link href="ch-kernel.en.html#s-customkernel" rel="section" title="10.2 What tools does Debian provide to build custom kernels?">
<link href="ch-kernel.en.html#s-custombootdisk" rel="section" title="10.3 How can I make a custom boot floppy?">
<link href="ch-kernel.en.html#s-modules" rel="section" title="10.4 What special provisions does Debian provide to deal with modules?">
<link href="ch-kernel.en.html#s-removeoldkernel" rel="section" title="10.5 Can I safely de-install an old kernel package, and if so, how?">
<link href="ch-customizing.en.html#s-papersize" rel="section" title="11.1 How can I ensure that all programs use the same paper size?">
<link href="ch-customizing.en.html#s-hardwareaccess" rel="section" title="11.2 How can I provide access to hardware peripherals, without compromising security?">
<link href="ch-customizing.en.html#s-consolefont" rel="section" title="11.3 How do I load a console font on startup the Debian way?">
<link href="ch-customizing.en.html#s-appdefaults" rel="section" title="11.4 How can I configure an X11 program's application defaults?">
<link href="ch-customizing.en.html#s-booting" rel="section" title="11.5 Every distribution seems to have a different boot-up method. Tell me about Debian's.">
<link href="ch-customizing.en.html#s-custombootscripts" rel="section" title="11.6 It looks as if Debian does not use rc.local to customize the boot process; what facilities are provided?">
<link href="ch-customizing.en.html#s-interconffiles" rel="section" title="11.7 How does the package management system deal with packages that contain configuration files for other packages?">
<link href="ch-customizing.en.html#s-divert" rel="section" title="11.8 How do I override a file installed by a package, so that a different version can be used instead?">
<link href="ch-customizing.en.html#s-localpackages" rel="section" title="11.9 How can I have my locally-built package included in the list of available packages that the package management system knows about?">
<link href="ch-customizing.en.html#s-diverse" rel="section" title="11.10 Some users like mawk, others like gawk; some like vim, others like elvis; some like trn, others like tin; how does Debian support diversity?">
<link href="ch-support.en.html#s-debiandocs" rel="section" title="12.1 What other documentation exists on and for a Debian system?">
<link href="ch-support.en.html#s-onlineresources" rel="section" title="12.2 Are there any on-line resources for discussing Debian?">
<link href="ch-support.en.html#s-searchtools" rel="section" title="12.3 Is there a quick way to search for information on Debian GNU/Linux?">
<link href="ch-support.en.html#s-buglogs" rel="section" title="12.4 Are there logs of known bugs?">
<link href="ch-support.en.html#s-bugreport" rel="section" title="12.5 How do I report a bug in Debian?">
<link href="ch-contributing.en.html#s-contrib" rel="section" title="13.1 How can I become a Debian software developer?">
<link href="ch-contributing.en.html#s-contribresources" rel="section" title="13.2 How can I contribute resources to the Debian project?">
<link href="ch-contributing.en.html#s-supportingorganizations" rel="section" title="13.3 How can I contribute financially to the Debian project?">
<link href="ch-redistrib.en.html#s-sellcds" rel="section" title="14.1 Can I make and sell Debian CDs?">
<link href="ch-redistrib.en.html#s-packagednonfree" rel="section" title="14.2 Can Debian be packaged with non-free software?">
<link href="ch-redistrib.en.html#s-childistro" rel="section" title="14.3 I am making a special Linux distribution for a &quot;vertical market&quot;. Can I use Debian GNU/Linux for the guts of a Linux system and add my own applications on top of it?">
<link href="ch-redistrib.en.html#s-commercialdebs" rel="section" title="14.4 Can I put my commercial program in a Debian &quot;package&quot; so that it installs effortlessly on any Debian system?">
<link href="ch-nexttime.en.html#s-i18n" rel="section" title="15.1 Extended support for non-English users">
<link href="ch-nexttime.en.html#s-dependencybasedboot" rel="section" title="15.2 Faster booting: Dependency based boot sequence">
<link href="ch-nexttime.en.html#s-di" rel="section" title="15.3 Improvements in the Debian Installer">
<link href="ch-nexttime.en.html#s-morearches" rel="section" title="15.4 More architectures">
<link href="ch-nexttime.en.html#s-morekernels" rel="section" title="15.5 More kernels">
<link href="ch-faqinfo.en.html#s-authors" rel="section" title="16.1 Authors">
<link href="ch-faqinfo.en.html#s-feedback" rel="section" title="16.2 Feedback">
<link href="ch-faqinfo.en.html#s-latest" rel="section" title="16.3 Availability">
<link href="ch-faqinfo.en.html#s-docformat" rel="section" title="16.4 Document format">
<link href="ch-choosing.en.html#s3.1.1" rel="subsection" title="3.1.1 You asked me to install stable, but in stable so and so hardware is not detected/working. What should I do?">
<link href="ch-choosing.en.html#s3.1.2" rel="subsection" title="3.1.2 Will there be different versions of packages in different distributions?">
<link href="ch-choosing.en.html#s3.1.3" rel="subsection" title="3.1.3 The stable distributions really contains outdated packages. Just look at Kde, Gnome, Xorg or even the kernel. They are very old. Why is it so?">
<link href="ch-choosing.en.html#s3.1.4" rel="subsection" title="3.1.4 If I were to decide to change to another distribution, Can I do that?">
<link href="ch-choosing.en.html#s3.1.5" rel="subsection" title="3.1.5 Could you tell me whether to install testing or unstable?">
<link href="ch-choosing.en.html#s3.1.6" rel="subsection" title="3.1.6 You are talking about testing being broken. What do you mean by that?">
<link href="ch-choosing.en.html#s3.1.7" rel="subsection" title="3.1.7 Why is it that testing could be broken for months? Wont the fixes introduced in unstable flow directly down into testing?">
<link href="ch-choosing.en.html#s3.1.8" rel="subsection" title="3.1.8 From an administrator's point of view, Which distribution requires more attention?">
<link href="ch-choosing.en.html#s3.1.9" rel="subsection" title="3.1.9 What happens when a new release is made?">
<link href="ch-choosing.en.html#s3.1.10" rel="subsection" title="3.1.10 I have a working Desktop/cluster with Debian installed. How do I know which distribution I am running?">
<link href="ch-choosing.en.html#s3.1.11" rel="subsection" title="3.1.11 I am currently tracking stable. Can I change to testing or unstable? If so, How?">
<link href="ch-choosing.en.html#s3.1.12" rel="subsection" title="3.1.12 I am currently tracking testing (wheezy). What will happen when a release is made? Will I still be tracking testing or will my machine be running the new stable distribution?">
<link href="ch-choosing.en.html#s3.1.13" rel="subsection" title="3.1.13 I am still confused. What did you say I should install?">
<link href="ch-choosing.en.html#s3.2.1" rel="subsection" title="3.2.1 I know that Knoppix/Linex/Ubuntu/... is Debian-based. So after installing it on the hard disk, can I use 'apt' package tools on it?">
<link href="ch-choosing.en.html#s3.2.2" rel="subsection" title="3.2.2 I installed Knoppix/Linex/Ubuntu/... on my hard disk. Now I have a problem. What should I do?">
<link href="ch-choosing.en.html#s3.2.3" rel="subsection" title="3.2.3 I'm using Knoppix/Linex/Ubuntu/... and now I want to use Debian. How do I migrate?">
<link href="ch-ftparchives.en.html#s-oldcodenames" rel="subsection" title="6.2.1 Which other codenames have been used in the past?">
<link href="ch-ftparchives.en.html#s-sourceforcodenames" rel="subsection" title="6.2.2 Where do these codenames come from?">
<link href="ch-ftparchives.en.html#s-frozen" rel="subsection" title="6.5.1 What about &quot;testing&quot;? How is it `frozen'?">
<link href="ch-pkgtools.en.html#s-dpkg" rel="subsection" title="8.1.1 dpkg">
<link href="ch-pkgtools.en.html#s-apt-get" rel="subsection" title="8.1.2 APT">
<link href="ch-pkgtools.en.html#s-aptitude" rel="subsection" title="8.1.3 aptitude">
<link href="ch-pkgtools.en.html#s-synaptic" rel="subsection" title="8.1.4 synaptic">
<link href="ch-pkgtools.en.html#s-tasksel" rel="subsection" title="8.1.5 tasksel">
<link href="ch-pkgtools.en.html#s-dpkg-extra" rel="subsection" title="8.1.6 Other package management tools">
<link href="ch-pkgtools.en.html#s-dselect" rel="subsection" title="8.1.6.1 dselect">
<link href="ch-pkgtools.en.html#s-dpkg-deb" rel="subsection" title="8.1.6.2 dpkg-deb">
<link href="ch-pkgtools.en.html#s-dpkg-split" rel="subsection" title="8.1.6.3 dpkg-split">
<link href="ch-uptodate.en.html#s-aptitude-upgrade" rel="subsection" title="9.1.1 aptitude">
<link href="ch-uptodate.en.html#s-apt" rel="subsection" title="9.1.2 apt-get, dselect and apt-cdrom">
<link href="ch-uptodate.en.html#s-update_aptitude" rel="subsection" title="9.1.3 aptitude">
<link href="ch-uptodate.en.html#s-mirror" rel="subsection" title="9.1.4 mirror">
<link href="ch-uptodate.en.html#s-dpkg-mountable" rel="subsection" title="9.1.5 dpkg-mountable">
<link href="ch-support.en.html#s12.2.1" rel="subsection" title="12.2.1 Mailing lists">
<link href="ch-support.en.html#s-mailinglistconduct" rel="subsection" title="12.2.1.1 What is the code of conduct for the mailing lists?">
<link href="ch-support.en.html#s12.2.2" rel="subsection" title="12.2.2 Web forums">
<link href="ch-support.en.html#s12.2.3" rel="subsection" title="12.2.3 Wiki">
<link href="ch-support.en.html#s12.2.4" rel="subsection" title="12.2.4 Maintainers">
<link href="ch-support.en.html#s12.2.5" rel="subsection" title="12.2.5 Usenet newsgroups">
<link href="ch-contributing.en.html#s-SPI" rel="subsection" title="13.3.1 Software in the Public Interest">
<link href="ch-contributing.en.html#s-FSF" rel="subsection" title="13.3.2 Free Software Foundation">

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<p><a name="ch-customizing"></a></p>
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<p>
[ <a href="ch-kernel.en.html">previous</a> ]
[ <a href="index.en.html#contents">Contents</a> ]
[ <a href="ch-basic_defs.en.html">1</a> ]
[ <a href="ch-getting.en.html">2</a> ]
[ <a href="ch-choosing.en.html">3</a> ]
[ <a href="ch-compat.en.html">4</a> ]
[ <a href="ch-software.en.html">5</a> ]
[ <a href="ch-ftparchives.en.html">6</a> ]
[ <a href="ch-pkg_basics.en.html">7</a> ]
[ <a href="ch-pkgtools.en.html">8</a> ]
[ <a href="ch-uptodate.en.html">9</a> ]
[ <a href="ch-kernel.en.html">10</a> ]
[ 11 ]
[ <a href="ch-support.en.html">12</a> ]
[ <a href="ch-contributing.en.html">13</a> ]
[ <a href="ch-redistrib.en.html">14</a> ]
[ <a href="ch-nexttime.en.html">15</a> ]
[ <a href="ch-faqinfo.en.html">16</a> ]
[ <a href="ch-support.en.html">next</a> ]
</p>

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<h1>
The Debian GNU/Linux FAQ
<br>Chapter 11 - Customizing your installation of Debian GNU/Linux
</h1>

<hr>

<h2><a name="s-papersize"></a>11.1 How can I ensure that all programs use the same paper size?</h2>

<p>
Install the <code>libpaper1</code> package, and it will ask you for a
system-wide default paper size.  This setting will be kept in the file
<samp>/etc/papersize</samp>.
</p>

<p>
Users can override the paper size setting using the <samp>PAPERSIZE</samp>
environment variable.  For details, see the manual page
<code>papersize(5)</code>.
</p>

<hr>

<h2><a name="s-hardwareaccess"></a>11.2 How can I provide access to hardware peripherals, without compromising security?</h2>

<p>
Many device files in the <samp>/dev</samp> directory belong to some predefined
groups.  For example, <samp>/dev/fd0</samp> belongs to the <samp>floppy</samp>
group, and <samp>/dev/dsp</samp> belongs to the <samp>audio</samp> group.
</p>

<p>
If you want a certain user to have access to one of these devices, just add the
user to the group the device belongs to, i.e.  do:
</p>

<pre>
     adduser user group
</pre>

<p>
This way you won't have to change the file permissions on the device.
</p>

<p>
If you do this from within a user's shell or a GUI environment you have to
logout and login again to become an effective member of that group.  To check
which groups you belong to run <samp>groups</samp>.
</p>

<p>
Notice that, since the introduction of <samp>udev</samp> if you change the
permissions of a hardware peripheral they might be be adjusted for some devices
when the system starts, if this happens to the hardware peripherals you are
instered in you will have to adjust the rules at <samp>/etc/udev</samp>.
</p>

<hr>

<h2><a name="s-consolefont"></a>11.3 How do I load a console font on startup the Debian way?</h2>

<p>
The <code>kbd</code> and <code>console-tools</code> packages support this, edit
<samp>/etc/kbd/config</samp> or <samp>/etc/console-tools/config</samp> files.
</p>

<hr>

<h2><a name="s-appdefaults"></a>11.4 How can I configure an X11 program's application defaults?</h2>

<p>
Debian's X programs will install their application resource data in the
<samp>/etc/X11/app-defaults/</samp> directory.  If you want to customize X
applications globally, put your customizations in those files.  They are marked
as configuration files, so their contents will be preserved during upgrades.
</p>

<hr>

<h2><a name="s-booting"></a>11.5 Every distribution seems to have a different boot-up method. Tell me about Debian's.</h2>

<p>
Like all Unices, Debian boots up by executing the program <samp>init</samp>.
The configuration file for <samp>init</samp> (which is
<samp>/etc/inittab</samp>) specifies that the first script to be executed
should be <samp>/etc/init.d/rcS</samp>.  This script runs all of the scripts in
<samp>/etc/rcS.d/</samp> by sourcing or forking subprocess depending on their
file extension to perform initialization such as to check and to mount file
systems, to load modules, to start the network services, to set the clock, and
to perform other initialization.  Then, for compatibility, it runs the files
(except those with a `.'in the filename) in <samp>/etc/rc.boot/</samp> too.
Any scripts in the latter directory are usually reserved for system
administrator use, and using them in packages is deprecated.
</p>

<p>
After completing the boot process, <samp>init</samp> executes all start scripts
in a directory specified by the default runlevel (this runlevel is given by the
entry for <samp>id</samp> in <samp>/etc/inittab</samp>).  Like most System V
compatible Unices, Linux has 7 runlevels:
</p>
<ul>
<li>
<p>
0 (halt the system),
</p>
</li>
</ul>
<ul>
<li>
<p>
1 (single-user mode),
</p>
</li>
</ul>
<ul>
<li>
<p>
2 through 5 (various multi-user modes), and
</p>
</li>
</ul>
<ul>
<li>
<p>
6 (reboot the system).
</p>
</li>
</ul>

<p>
Debian systems come with id=2, which indicates that the default runlevel will
be '2' when the multi-user state is entered, and the scripts in
<samp>/etc/rc2.d/</samp> will be run.
</p>

<p>
In fact, the scripts in any of the directories, <samp>/etc/rcN.d/</samp> are
just symbolic links back to scripts in <samp>/etc/init.d/</samp>.  However, the
<em>names</em> of the files in each of the <samp>/etc/rcN.d/</samp> directories
are selected to indicate the <em>way</em> the scripts in
<samp>/etc/init.d/</samp> will be run.  Specifically, before entering any
runlevel, all the scripts beginning with 'K' are run; these scripts kill
services.  Then all the scripts beginning with 'S' are run; these scripts start
services.  The two-digit number following the 'K' or 'S' indicates the order in
which the script is run.  Lower numbered scripts are executed first.
</p>

<p>
This approach works because the scripts in <samp>/etc/init.d/</samp> all take
an argument which can be either `start', `stop', `reload', `restart' or
`force-reload' and will then do the task indicated by the argument.  These
scripts can be used even after a system has been booted, to control various
processes.
</p>

<p>
For example, with the argument `reload' the command
</p>

<pre>
     /etc/init.d/sendmail reload
</pre>

<p>
sends the sendmail daemon a signal to reread its configuration file.  (BTW,
Debian supplies <code>invoke-rc.d</code> as a wrapper for invoking the scripts
in <samp>/etc/init.d/</samp>.)
</p>

<hr>

<h2><a name="s-custombootscripts"></a>11.6 It looks as if Debian does not use <samp>rc.local</samp> to customize the boot process; what facilities are provided?</h2>

<p>
Suppose a system needs to execute script <samp>foo</samp> on start-up, or on
entry to a particular (System V) runlevel.  Then the system administrator
should:
</p>
<ul>
<li>
<p>
Enter the script <samp>foo</samp> into the directory <samp>/etc/init.d/</samp>.
</p>
</li>
</ul>
<ul>
<li>
<p>
Run the Debian command <samp>update-rc.d</samp> with appropriate arguments, to
specify which runlevels should start the service, and which runlevels should
stop the service.
</p>
</li>
</ul>
<ul>
<li>
<p>
Consider rebooting the system to check that the service starts correctly
(assuming that you've asked for it to be started in the default runlevel).
Otherwise, manually start it by running `<samp>/etc/init.d/foo start</samp>'.
</p>
</li>
</ul>

<p>
One might, for example, cause the script <samp>foo</samp> to execute at
boot-up, by putting it in <samp>/etc/init.d/</samp> and running
<samp>update-rc.d foo defaults 19</samp>.  The argument `<samp>defaults</samp>'
refers to the default runlevels, which means (at least in absence of any LSB
comment block to the contrary) to start the service in runlevels 2 through 5,
and to stop the service in runlevels 0, 1 and 6.  (Any LSB Default-Start and
Default-Stop directives in <samp>foo</samp> take precedence when using the
sysv-rc version of update-rc.d, but are ignored by the current (v0.8.10)
file-rc version of update-rc.d.) The argument `<samp>19</samp>' ensures that
<samp>foo</samp> is called after all scripts whose number is less than 19 have
completed, and before all scripts whose number is 20 or greater.
</p>

<hr>

<h2><a name="s-interconffiles"></a>11.7 How does the package management system deal with packages that contain configuration files for other packages?</h2>

<p>
Some users wish to create, for example, a new server by installing a group of
Debian packages and a locally generated package consisting of configuration
files.  This is not generally a good idea, because <code>dpkg</code> will not
know about those configuration files if they are in a different package, and
may write conflicting configurations when one of the initial &quot;group&quot;
of packages is upgraded.
</p>

<p>
Instead, create a local package that modifies the configuration files of the
&quot;group&quot; of Debian packages of interest.  Then <code>dpkg</code> and
the rest of the package management system will see that the files have been
modified by the local &quot;sysadmin&quot; and will not try to overwrite them
when those packages are upgraded.
</p>

<hr>

<h2><a name="s-divert"></a>11.8 How do I override a file installed by a package, so that a different version can be used instead?</h2>

<p>
Suppose a sysadmin or local user wishes to use a program
&quot;login-local&quot; rather than the program &quot;login&quot; provided by
the Debian <code>login</code> package.
</p>

<p>
Do <strong>not</strong>:
</p>
<ul>
<li>
<p>
Overwrite <samp>/bin/login</samp> with <samp>login-local</samp>.
</p>
</li>
</ul>

<p>
The package management system will not know about this change, and will simply
overwrite your custom <samp>/bin/login</samp> whenever <samp>login</samp> (or
any package that provides <samp>/bin/login</samp>) is installed or updated.
</p>

<p>
Rather, do
</p>
<ul>
<li>
<p>
Execute:
</p>

<pre>
     dpkg-divert --divert /bin/login.debian /bin/login
</pre>

<p>
in order to cause all future installations of the Debian <code>login</code>
package to write the file <samp>/bin/login</samp> to
<samp>/bin/login.debian</samp> instead.
</p>
</li>
</ul>
<ul>
<li>
<p>
Then execute:
</p>

<pre>
     cp login-local /bin/login
</pre>

<p>
to move your own locally-built program into place.
</p>
</li>
</ul>

<p>
Run <samp>dpkg-divert --list</samp> to see which diversions are currently
active on your system.
</p>

<p>
Details are given in the manual page <code>dpkg-divert(8)</code>.
</p>

<hr>

<h2><a name="s-localpackages"></a>11.9 How can I have my locally-built package included in the list of available packages that the package management system knows about?</h2>

<p>
Execute the command:
</p>

<pre>
     dpkg-scanpackages BIN_DIR OVERRIDE_FILE [PATHPREFIX] &gt; my_Packages
</pre>

<p>
where:
</p>
<ul>
<li>
<p>
BIN-DIR is a directory where Debian archive files (which usually have an
extension of &quot;.deb&quot;) are stored.
</p>
</li>
</ul>
<ul>
<li>
<p>
OVERRIDE_FILE is a file that is edited by the distribution maintainers and is
usually stored on a Debian FTP archive at <samp>indices/override.main.gz</samp>
for the Debian packages in the &quot;main&quot; distribution.  You can ignore
this for local packages.
</p>
</li>
</ul>
<ul>
<li>
<p>
PATHPREFIX is an <em>optional</em> string that can be prepended to the
<samp>my_Packages</samp> file being produced.
</p>
</li>
</ul>

<p>
Once you have built the file <samp>my_Packages</samp>, tell the package
management system about it by using the command:
</p>

<pre>
     dpkg --merge-avail my_Packages
</pre>

<p>
If you are using APT, you can add the local repository to your
<code>sources.list(5)</code> file, too.
</p>

<hr>

<h2><a name="s-diverse"></a>11.10 Some users like mawk, others like gawk; some like vim, others like elvis; some like trn, others like tin; how does Debian support diversity?</h2>

<p>
There are several cases where two packages provide two different versions of a
program, both of which provide the same core functionality.  Users might prefer
one over another out of habit, or because the user interface of one package is
somehow more pleasing than the interface of another.  Other users on the same
system might make a different choice.
</p>

<p>
Debian uses a &quot;virtual&quot; package system to allow system administrators
to choose (or let users choose) their favorite tools when there are two or more
that provide the same basic functionality, yet satisfy package dependency
requirements without specifying a particular package.
</p>

<p>
For example, there might exist two different versions of newsreaders on a
system.  The news server package might 'recommend' that there exist
<em>some</em> news reader on the system, but the choice of <samp>tin</samp> or
<samp>trn</samp> is left up to the individual user.  This is satisfied by
having both the <code>tin</code> and <code>trn</code> packages provide the
virtual package <code>news-reader</code>.  <em>Which</em> program is invoked is
determined by a link pointing from a file with the virtual package name
<samp>/etc/alternatives/news-reader</samp> to the selected file, e.g.,
<samp>/usr/bin/trn</samp>.
</p>

<p>
A single link is insufficient to support full use of an alternate program;
normally, manual pages, and possibly other supporting files must be selected as
well.  The Perl script <samp>update-alternatives</samp> provides a way of
ensuring that all the files associated with a specified package are selected as
a system default.
</p>

<p>
For example, to check what executables provide `x-window-manager', run:
</p>

<pre>
     update-alternatives --display x-window-manager
</pre>

<p>
If you want to change it, run:
</p>

<pre>
     update-alternatives --config x-window-manager
</pre>

<p>
And follow the instructions on the screen (basically, press the number next to
the entry you'd like better).
</p>

<p>
If a package doesn't register itself as a window manager for some reason (file
a bug if it's in error), or if you use a window manager from /usr/local
directory, the selections on screen won't contain your preferred entry.  You
can update the link through command line options, like this:
</p>

<pre>
     update-alternatives --install /usr/bin/x-window-manager \
       x-window-manager /usr/local/bin/wmaker-cvs 50
</pre>

<p>
The first argument to `--install' option is the symlink that points to
/etc/alternatives/NAME, where NAME is the second argument.  The third argument
is the program to which /etc/alternatives/NAME should point to, and the fourth
argument is the priority (larger value means the alternative will more probably
get picked automatically).
</p>

<p>
To remove an alternative you added, simply run:
</p>

<pre>
     update-alternatives --remove x-window-manager /usr/local/bin/wmaker-cvs
</pre>

<hr>

<p>
[ <a href="ch-kernel.en.html">previous</a> ]
[ <a href="index.en.html#contents">Contents</a> ]
[ <a href="ch-basic_defs.en.html">1</a> ]
[ <a href="ch-getting.en.html">2</a> ]
[ <a href="ch-choosing.en.html">3</a> ]
[ <a href="ch-compat.en.html">4</a> ]
[ <a href="ch-software.en.html">5</a> ]
[ <a href="ch-ftparchives.en.html">6</a> ]
[ <a href="ch-pkg_basics.en.html">7</a> ]
[ <a href="ch-pkgtools.en.html">8</a> ]
[ <a href="ch-uptodate.en.html">9</a> ]
[ <a href="ch-kernel.en.html">10</a> ]
[ 11 ]
[ <a href="ch-support.en.html">12</a> ]
[ <a href="ch-contributing.en.html">13</a> ]
[ <a href="ch-redistrib.en.html">14</a> ]
[ <a href="ch-nexttime.en.html">15</a> ]
[ <a href="ch-faqinfo.en.html">16</a> ]
[ <a href="ch-support.en.html">next</a> ]
</p>

<hr>

<p>
The Debian GNU/Linux FAQ
</p>

<address>
version 5.0ubuntu1, 20 October 2011<br>
<br>
Authors are listed at <a href="ch-faqinfo.en.html#s-authors">Debian FAQ Authors</a><br>
<br>
</address>
<hr>

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