X-Git-Url: https://git.saurik.com/apt.git/blobdiff_plain/e29dfa9ebfe9940089697fbb3e436e8ff95ecad6..1408e219e76e577fb84ef1c48e58337b6569feec:/doc/apt_preferences.5.xml?ds=sidebyside diff --git a/doc/apt_preferences.5.xml b/doc/apt_preferences.5.xml index 12b03196a..abcf56744 100644 --- a/doc/apt_preferences.5.xml +++ b/doc/apt_preferences.5.xml @@ -14,12 +14,13 @@ &apt-email; &apt-product; <!-- The last update date --> - <date>29 February 2004</date> + <date>16 February 2010</date> </refentryinfo> <refmeta> <refentrytitle>apt_preferences</refentrytitle> <manvolnum>5</manvolnum> + <refmiscinfo class="manual">APT</refmiscinfo> </refmeta> <!-- Man page title --> @@ -31,7 +32,8 @@ <refsect1> <title>Description</title> <para>The APT preferences file <filename>/etc/apt/preferences</filename> -can be used to control which versions of packages will be selected +and the fragment files in the <filename>/etc/apt/preferences.d/</filename> +folder can be used to control which versions of packages will be selected for installation.</para> <para>Several versions of a package may be available for installation when @@ -51,6 +53,24 @@ earliest in the &sources-list; file. The APT preferences file does not affect the choice of instance, only the choice of version.</para> +<para>Preferences are a strong power in the hands of a system administrator +but they can become also their biggest nightmare if used without care! +APT will not questioning the preferences so wrong settings will therefore +lead to uninstallable packages or wrong decisions while upgrading packages. +Even more problems will arise if multiply distribution releases are mixed +without a good understanding of the following paragraphs. +Packages included in a specific release aren't tested in and +therefore doesn't always work as expected in older or newer releases or +together with other packages from different releases. +You have been warned.</para> + +<para>Note that the files in the <filename>/etc/apt/preferences.d</filename> +directory are parsed in alphanumeric ascending order and need to obey the +following naming convention: The files have no or "<literal>pref</literal>" +as filename extension and which only contain alphanumeric, hyphen (-), +underscore (_) and period (.) characters - otherwise they will be silently +ignored.</para> + <refsect2><title>APT's Default Priority Assignments</title> <para>If there is no preferences file or if there is no entry in the file @@ -60,6 +80,9 @@ belongs. It is possible to single out a distribution, "the target release", which receives a higher priority than other distributions do by default. The target release can be set on the <command>apt-get</command> command line or in the APT configuration file <filename>/etc/apt/apt.conf</filename>. +Note that this has precedence over any general priority you set in the +<filename>/etc/apt/preferences</filename> file described later, but not +over specifically pinned packages. For example, <programlisting> @@ -74,6 +97,12 @@ APT::Default-Release "stable"; algorithm to set the priorities of the versions of a package. Assign: <variablelist> +<varlistentry> +<term>priority 1</term> +<listitem><simpara>to the versions coming from archives which in their <filename>Release</filename> +files are marked as "NotAutomatic: yes" like the debian experimental archive.</simpara></listitem> +</varlistentry> + <varlistentry> <term>priority 100</term> <listitem><simpara>to the version that is already installed (if any).</simpara></listitem> @@ -93,7 +122,9 @@ algorithm to set the priorities of the versions of a package. Assign: <para>If the target release has not been specified then APT simply assigns priority 100 to all installed package versions and priority 500 to all -uninstalled package versions.</para> +uninstalled package versions, expect versions coming from archives which +in their <filename>Release</filename> files are marked as "NotAutomatic: yes" - +these versions get the priority 1.</para> <para>APT then applies the following rules, listed in order of precedence, to determine which version of a package to install. @@ -143,10 +174,11 @@ separated by blank lines. Records can have one of two forms, a specific form and a general form. <itemizedlist> <listitem> -<simpara>The specific form assigns a priority (a "Pin-Priority") to a -specified package and specified version or version range. For example, +<simpara>The specific form assigns a priority (a "Pin-Priority") to one or more +specified packages and specified version or version range. For example, the following record assigns a high priority to all versions of -the <filename>perl</filename> package whose version number begins with "<literal>5.8</literal>".</simpara> +the <filename>perl</filename> package whose version number begins with "<literal>5.8</literal>". +Multiple packages can be separated by spaces.</simpara> <programlisting> Package: perl @@ -171,8 +203,15 @@ Pin: origin "" Pin-Priority: 999 </programlisting> -<simpara>A note of caution: the keyword used here is "<literal>origin</literal>". -This should not be confused with the Origin of a distribution as +<simpara>A note of caution: the keyword used here is "<literal>origin</literal>" +which can be used to match a hostname. The following record will assign a high priority +to all versions available from the server identified by the hostname "ftp.de.debian.org"</simpara> +<programlisting> +Package: * +Pin: origin "ftp.de.debian.org" +Pin-Priority: 999 +</programlisting> +<simpara>This should <emphasis>not</emphasis> be confused with the Origin of a distribution as specified in a <filename>Release</filename> file. What follows the "Origin:" tag in a <filename>Release</filename> file is not an Internet address but an author or vendor name, such as "Debian" or "Ximian".</simpara> @@ -183,7 +222,16 @@ belonging to any distribution whose Archive name is "<literal>unstable</literal> <programlisting> Package: * Pin: release a=unstable -Pin-Priority: 500 +Pin-Priority: 50 +</programlisting> + +<simpara>The following record assigns a high priority to all package versions +belonging to any distribution whose Codename is "<literal>&testing-codename;</literal>".</simpara> + +<programlisting> +Package: * +Pin: release n=&testing-codename; +Pin-Priority: 900 </programlisting> <simpara>The following record assigns a high priority to all package versions @@ -315,7 +363,7 @@ APT priorities: <para>The <filename>Release</filename> file is normally found in the directory <filename>.../dists/<replaceable>dist-name</replaceable></filename>: for example, <filename>.../dists/stable/Release</filename>, -or <filename>.../dists/woody/Release</filename>. +or <filename>.../dists/&stable-codename;/Release</filename>. It consists of a single multi-line record which applies to <emphasis>all</emphasis> of the packages in the directory tree below its parent. Unlike the <filename>Packages</filename> file, nearly all of the lines in a <filename>Release</filename> @@ -323,10 +371,11 @@ file are relevant for setting APT priorities: <variablelist> <varlistentry> -<term>the <literal>Archive:</literal> line</term> +<term>the <literal>Archive:</literal> or <literal>Suite:</literal> line</term> <listitem><simpara>names the archive to which all the packages in the directory tree belong. For example, the line -"Archive: stable" +"Archive: stable" or +"Suite: stable" specifies that all of the packages in the directory tree below the parent of the <filename>Release</filename> file are in a <literal>stable</literal> archive. Specifying this value in the APT preferences file @@ -338,6 +387,22 @@ Pin: release a=stable </listitem> </varlistentry> +<varlistentry> +<term>the <literal>Codename:</literal> line</term> +<listitem><simpara>names the codename to which all the packages +in the directory tree belong. For example, the line +"Codename: &testing-codename;" +specifies that all of the packages in the directory +tree below the parent of the <filename>Release</filename> file belong to a version named +<literal>&testing-codename;</literal>. Specifying this value in the APT preferences file +would require the line: +</simpara> +<programlisting> +Pin: release n=&testing-codename; +</programlisting> +</listitem> +</varlistentry> + <varlistentry> <term>the <literal>Version:</literal> line</term> <listitem><simpara>names the release version. For example, the @@ -419,10 +484,6 @@ distribution.</para> <para>Each record in the APT preferences file can optionally begin with one or more lines beginning with the word <literal>Explanation:</literal>. This provides a place for comments.</para> - -<para>The <literal>Pin-Priority:</literal> line in each APT preferences record is -optional. If omitted, APT assigs a priority of 1 less than the last value -specified on a line beginning with <literal>Pin-Priority: release ...</literal>.</para> </refsect2> </refsect1> @@ -518,10 +579,74 @@ version. apt-get install <replaceable>package</replaceable>/unstable </programlisting> </para> +</refsect2> + + +<refsect2> +<title>Tracking the evolution of a codename release</title> + +<para>The following APT preferences file will cause APT to assign a +priority higher than the default (500) to all package versions belonging +to a specified codename of a distribution and a prohibitively low priority to +package versions belonging to other <literal>Debian</literal> distributions, +codenames and archives. +Note that with this APT preference APT will follow the migration of a release +from the archive <literal>testing</literal> to <literal>stable</literal> and +later <literal>oldstable</literal>. If you want to follow for example the progress +in <literal>testing</literal> notwithstanding the codename changes you should use +the example configurations above. + +<programlisting> +Explanation: Uninstall or do not install any Debian-originated package versions +Explanation: other than those in the distribution codenamed with &testing-codename; or sid +Package: * +Pin: release n=&testing-codename; +Pin-Priority: 900 + +Explanation: Debian unstable is always codenamed with sid +Package: * +Pin: release n=sid +Pin-Priority: 800 + +Package: * +Pin: release o=Debian +Pin-Priority: -10 +</programlisting> +</para> +<para>With a suitable &sources-list; file and the above preferences file, +any of the following commands will cause APT to upgrade to the +latest version(s) in the release codenamed with <literal>&testing-codename;</literal>. + +<programlisting> +apt-get install <replaceable>package-name</replaceable> +apt-get upgrade +apt-get dist-upgrade +</programlisting> +</para> + +<para>The following command will cause APT to upgrade the specified +package to the latest version from the <literal>sid</literal> distribution. +Thereafter, <command>apt-get upgrade</command> will upgrade +the package to the most recent <literal>&testing-codename;</literal> version if that is +more recent than the installed version, otherwise, to the most recent +<literal>sid</literal> version if that is more recent than the installed +version. + +<programlisting> +apt-get install <replaceable>package</replaceable>/sid +</programlisting> +</para> </refsect2> </refsect1> +<refsect1> +<title>Files</title> + <variablelist> + &file-preferences; + </variablelist> +</refsect1> + <refsect1> <title>See Also</title> <para>&apt-get; &apt-cache; &apt-conf; &sources-list; @@ -531,4 +656,3 @@ apt-get install <replaceable>package</replaceable>/unstable &manbugs; </refentry> -