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- Committer: Bazaar Package Importer
- Author(s): Josip Rodin
- Date: 2002-04-30 19:02:09 UTC
- Revision ID: james.westby@ubuntu.com-20020430190209-v94hhhb9wj0kz552
Tags: 3.0
* Updated for the imminent woody release.
* Updated BTS docs from the FTP site, closes: #133422, #133440.
* Updated description of frozen, closes: #142801.
* Built a PDF version.
* Updated BTS docs from the FTP site, closes: #133422, #133440.
* Updated description of frozen, closes: #142801.
* Built a PDF version.
- files added:
- .bzr-builddeb
- FAQ
- debian
- doc
- doc-base
added
removed
FAQ/customizing.sgml
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<chapt id="customizing">Customizing your installation of &debian;
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<sect id="papersize">How can I ensure that all programs use the same
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paper size?
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<p>Install the <package/libpaperg/ package, and it will ask you for a
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system-wide default paper size. This setting will be kept in the file
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<tt>/etc/papersize</tt>.
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<p>Users can override the paper size setting using the <tt>PAPERSIZE</tt>
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environment variable. For details, see the manual page
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<manref name="papersize" section="5">.
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<sect id="hardwareaccess">How can I provide access to hardware peripherals,
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without compromising security?
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<p>Many device files in the <tt>/dev</tt> directory belong to some
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predefined groups. For example, <tt>/dev/fd0</tt> belongs to the
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<tt>floppy</tt> group, and <tt>/dev/dsp</tt> belongs to the
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<tt>audio</tt> group.
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<p>If you want a certain user to have access to one of these devices, just
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add the user to the group the device belongs to, i.e. do:
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<example>adduser user group</example>
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This way you won't have to chmod the device file.
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<sect id="consolefont">How do I load a console font on startup the Debian way?
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<p>The <package/kbd/ and <package/console-tools/ packages support this,
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edit <tt>/etc/kbd/config</tt> or <tt>/etc/console-tools/config</tt> files.
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<sect id="appdefaults">How can I configure an X11 program's application
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defaults?
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<p>Debian's X programs will install their application resource data in the
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<tt>/etc/X11/app-defaults/</tt> directory. If you want to customize X
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applications globally, put your customizations in those files. They are
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marked as configuration files, so their contents will be preserved during
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upgrades.
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<sect id="booting">Every distribution seems to have a different boot-up
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method. Tell me about Debian's.
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<p>Like all Unices, Debian boots up by executing the program <tt>init</tt>.
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The configuration file for <tt>init</tt> (which is <tt>/etc/inittab</tt>)
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specifies that the first script to be executed should
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be <tt>/etc/init.d/rcS</tt>. This script checks and mounts file systems,
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loads modules, starts the network services, sets the clock, performs other
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initialization, and then runs all of the scripts (except those with a `.'
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in the filename) in <tt>/etc/rc.boot/</tt>. Any scripts in the latter
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directory are usually reserved for system administrator use, and using them
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in packages is deprecated.
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<p>After completing the boot process, <tt>init</tt> executes all start
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scripts in a directory specified by the default runlevel (this runlevel
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is given by the entry for <tt>id</tt> in <tt>/etc/inittab</tt>).
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Like most <!-- all? SGK --> System V compatible Unices, Linux has 7 runlevels:
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<list>
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<item>0 (halt the system),
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<item>1 (single-user mode),
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<item>2 through 5 (various multi-user modes), and
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<item>6 (reboot the system).
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</list>
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Debian systems come with id=2, which indicates that the default
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runlevel will be '2' when the multi-user state is entered, and the
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scripts in <tt>/etc/rc2.d/</tt> will be run.
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<p>In fact, the scripts in any of the directories, <tt>/etc/rcN.d/</tt>
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are just symbolic links back to scripts in <tt>/etc/init.d/</tt>. However,
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the <em>names</em> of the files in each of the <tt>/etc/rcN.d/</tt>
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directories are selected to indicate the <em>way</em> the scripts in
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<tt>/etc/init.d/</tt> will be run. Specifically, before entering any
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runlevel, all the scripts beginning with 'K' are run; these scripts kill
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services. Then all the scripts beginning with 'S' are run; these scripts
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start services. The two-digit number following the 'K' or 'S' indicates
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the order in which the script is run. Lower numbered scripts are executed
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first.
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<p>This approach works because the scripts in <tt>/etc/init.d/</tt> all
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take an argument which can be either `start', `stop', `reload', `restart'
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or `force-reload' and will then do the task indicated by the argument.
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These scripts can be used even after a system has been booted, to control
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various processes.
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<p>For example, with the argument `reload' the command
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<example>/etc/init.d/sendmail reload</example>
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sends the sendmail daemon a signal to reread its configuration file.
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<sect id="custombootscripts">It looks as if Debian does not use
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<tt>rc.local</tt> to customize the boot process; what facilities
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are provided?
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<p>Suppose a system needs to execute script <tt>foo</tt> on start-up,
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or on entry to a particular (System V) runlevel. Then the system
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administrator should:
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<list>
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<item>Enter the script <tt>foo</tt> into the directory <tt>/etc/init.d/</tt>.
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<item>Run the Debian command <tt>update-rc.d</tt> with appropriate
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arguments, to set up links between the (command-line-specified) directories
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rc?.d and <tt>/etc/init.d/foo</tt>. Here, '?' is a number from 0 through 6
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and corresponds to each of the System V runlevels.
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<item>Reboot the system.
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</list>
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<p>The command <tt>update-rc.d</tt> will set up links between files in
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the directories rc?.d and the script in <tt>/etc/init.d/</tt>.
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Each link will begin with a 'S' or a 'K', followed by a number, followed
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by the name of the script. Scripts beginning with 'S' in
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<tt>/etc/rcN.d/</tt> are executed when runlevel <tt>N</tt> is entered.
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Scripts beginning with a 'K' are executed when leaving runlevel <tt>N</tt>.
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<p>One might, for example, cause the script <tt>foo</tt> to execute at
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boot-up, by putting it in <tt>/etc/init.d/</tt> and installing the links with
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<tt>update-rc.d foo defaults 19</tt>. The argument 'defaults' refers
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to the default runlevels, which are 2 through 5. The argument '19' ensures
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that <tt>foo</tt> is called before any scripts containing numbers 20
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or larger.
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<sect id="interconffiles">How does the package management system deal with
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packages that contain configuration files for other packages?
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<p>Some users wish to create, for example, a new server by installing a
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group of Debian packages and a locally generated package consisting of
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configuration files. This is not generally a good idea, because <prgn/dpkg/
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will not know about those configuration files if they are in a different
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package, and may write conflicting configurations when one of the
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initial "group" of packages is upgraded.
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<p>Instead, create a local package that modifies the configuration files
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of the "group" of Debian packages of interest. Then <prgn/dpkg/ and the
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rest of the package management system will see that the files have been
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modified by the local "sysadmin" and will not try to overwrite them when
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those packages are upgraded.
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<!-- check against dpkg-divert description -->
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<sect id="divert">How do I override a file installed by a package, so that
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a different version can be used instead?
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<p>Suppose a sysadmin or local user wishes to use a program "login-local"
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rather than the program "login" provided by the Debian <package/login/
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package.
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<p>Do <strong/not/:
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<list>
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<item>Overwrite <tt>/bin/login</tt> with <tt>login-local</tt>.
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</list>
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The package management system will not know about this change, and will simply
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overwrite your custom <tt>/bin/login</tt> whenever <tt>login</tt> (or any
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package that provides <tt>/bin/login</tt>) is installed or updated.
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<!-- XXX dpkg-divert: is this correct ? -->
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<p>Rather, do
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<list>
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<item>Execute:
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<example>dpkg-divert --divert /bin/login.debian /bin/login</example>
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in order to cause all future installations of the Debian <package/login/
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package to write the file <tt>/bin/login</tt> to <tt>/bin/login.debian</tt>
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instead.
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<item>Then execute:
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<example>cp login-local /bin/login</example>
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to move your own locally-built program into place.
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</list>
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<p>Details are given in the manual page <manref name="dpkg-divert" section="8">.
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<sect id="localpackages">How can I have my locally-built package included in
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the list of available packages that the package management system knows
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about?
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<p>Execute the command:
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<example>
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dpkg-scanpackages BIN_DIR OVERRIDE_FILE [PATHPREFIX] > my_Packages
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</example>
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<p>where:
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<list>
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<item>BIN-DIR is a directory where Debian archive files (which usually
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have an extension of ".deb") are stored.
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<item>OVERRIDE_FILE is a file that is edited by the distribution
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maintainers and is usually stored on a Debian FTP archive at
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<tt>indices/override.main.gz</tt> for the Debian packages in
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the "main" distribution. You can ignore this for local packages.
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<item>PATHPREFIX is an <em>optional</em> string that can be prepended
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to the <tt>my_Packages</tt> file being produced.
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</list>
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<p>Once you have built the file <tt>my_Packages</tt>, tell the package
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management system about it by using the command:
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<example>
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dpkg --merge-avail my_Packages
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</example>
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<p>If you are using APT, you can add the local repository to your
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<manref name="sources.list" section="5"> file, too.
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<sect id="diverse">Some users like mawk, others like gawk; some like vim,
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others like elvis; some like trn, others like tin; how does Debian
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support diversity?
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<p>There are several cases where two packages provide two different versions
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of a program, both of which provide the same core functionality. Users
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might prefer one over another out of habit, or because the user
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interface of one package is somehow more pleasing than the interface of
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another. Other users on the same system might make a different choice.
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<p>Debian uses a "virtual" package system to allow system administrators
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to choose (or let users choose) their favorite tools when there are two
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or more that provide the same basic functionality, yet satisfy package
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dependency requirements without specifying a particular package.
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<p>For example, there might exist two different versions of newsreaders on
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a system. The news server package might 'recommend' that there exist
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<em>some</em> news reader on the system, but the choice of <tt>tin</tt>
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or <tt>trn</tt> is left up to the individual user. This is satisfied by
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having both the <package/tin/ and <package/trn/ packages provide the
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virtual package <package/news-reader/. <em>Which</em> program is
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invoked is determined by a link pointing from a file with the virtual
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package name <tt>/etc/alternatives/news-reader</tt> to the selected file,
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e.g., <tt>/usr/bin/trn</tt>.
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<p>A single link is insufficient to support full use of an alternate
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program; normally, manual pages, and possibly other supporting files
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must be selected as well. The Perl script <tt>update-alternatives</tt>
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provides a way of ensuring that all the files associated with a specified
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package are selected as a system default.
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<p>For example, to check what executables provide `x-window-manager', run:
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<example>update-alternatives --display x-window-manager</example>
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If you want to change it, run:
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<example>update-alternatives --config x-window-manager</example>
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And follow the instructions on the screen (basically, press the number
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next to the entry you'd like better).
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<p>If a package doesn't register itself as a window manager for some reason
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(file a bug if it's in error), or if you use a window manager from /usr/local
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directory, the selections on screen won't contain your preferred entry.
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You can update the link through command line options, like this:
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<example>update-alternatives --install /usr/bin/x-window-manager \
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x-window-manager /usr/local/bin/wmaker-cvs 50</example>
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<p>The first argument to `--install' option is the symlink that points to
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/etc/alternatives/NAME, where NAME is the second argument. The third argument
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is the program to which /etc/alternatives/NAME should point to, and the
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fourth argument is the priority (larger value means the alternative will more
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probably get picked automatically).
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<p>To remove an alternative you added, simply run:
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<example>update-alternatives --remove x-window-manager /usr/local/bin/wmaker-cvs</example>
Loggerhead is a web-based interface for Breezy
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