* Document unit for Cache-Limit (bytes) (Closes: #234737)

[apt.git] / doc / apt-get.8.xml

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<refentry>
 &apt-docinfo;
 <!--<date>14 December 2003</date> -->
 
 <refmeta>
   <refentrytitle>apt-get</refentrytitle>
   <manvolnum>8</manvolnum>
 </refmeta>
 
 <!-- Man page title -->
 <refnamediv>
    <refname>apt-get</refname>
    <refpurpose>APT package handling utility -- command-line interface</refpurpose>
 </refnamediv>

 <!-- Arguments -->
 <refsynopsisdiv>
   <cmdsynopsis>
      <command>apt-get</command>
      <arg><option>-hvs</option></arg>
      <arg><option>-o=<replaceable>config string</replaceable></option></arg>
      <arg><option>-c=<replaceable>file</replaceable></option></arg>
      <group choice="req">
         <arg>update</arg>
         <arg>upgrade</arg>
         <arg>dselect-upgrade</arg>
         <arg>install <arg choice="plain" rep="repeat"><replaceable>pkg</replaceable></arg></arg>
         <arg>remove <arg choice="plain" rep="repeat"><replaceable>pkg</replaceable></arg></arg>
         <arg>source <arg choice="plain" rep="repeat"><replaceable>pkg</replaceable></arg></arg>
         <arg>build-dep <arg choice="plain" rep="repeat"><replaceable>pkg</replaceable></arg></arg>
         <arg>check</arg>
         <arg>clean</arg>
         <arg>autoclean</arg>
      </group>   
   </cmdsynopsis>
 </refsynopsisdiv>
 
 <refsect1><title>Description</title>
   <para><command>apt-get</command> is the command-line tool for handling packages, and may be 
   considered the user's "back-end" to other tools using the APT
   library.  Several "front-end" interfaces exist, such as dselect(8),
   aptitude, synaptic, gnome-apt and wajig.</para>

   <para>Unless the <option>-h</option>, or <option>--help</option> option is given, one of the
   commands below must be present.</para>
   
   <variablelist>
     <varlistentry><term>update</term>
     <listitem><para><literal>update</literal> is used to resynchronize the package index files from
     their sources. The indexes of available packages are fetched from the
     location(s) specified in <filename>/etc/apt/sources.list</filename>.
     For example, when using a Debian archive, this command retrieves and
     scans the <filename>Packages.gz</filename> files, so that information about new 
     and updated packages is available. An <literal>update</literal> should always be 
     performed before an <literal>upgrade</literal> or <literal>dist-upgrade</literal>. Please 
     be aware that the overall progress meter will be incorrect as the size 
     of the package files cannot be known in advance.</para></listitem>
     </varlistentry>
     
     <varlistentry><term>upgrade</term>
     <listitem><para><literal>upgrade</literal> is used to install the newest versions of all packages 
     currently installed on the system from the sources enumerated in
     <filename>/etc/apt/sources.list</filename>. Packages currently installed with 
     new versions available are retrieved and upgraded; under no circumstances 
     are currently installed packages removed, or packages not already installed 
     retrieved and installed. New versions of currently installed packages that 
     cannot be upgraded without changing the install status of another package 
     will be left at their current version. An <literal>update</literal> must be 
     performed first so that <command>apt-get</command> knows that new versions of packages are 
     available.</para></listitem>
     </varlistentry>

     <varlistentry><term>dselect-upgrade</term>
     <listitem><para><literal>dselect-upgrade</literal>
     is used in conjunction with the traditional Debian packaging
     front-end, &dselect;. <literal>dselect-upgrade</literal>
     follows the changes made by &dselect; to the <literal>Status</literal>
     field of available packages, and performs the actions necessary to realize
     that state (for instance, the removal of old and the installation of new
     packages).</para></listitem>
     </varlistentry>

     <varlistentry><term>dist-upgrade</term>
     <listitem><para><literal>dist-upgrade</literal> in addition to performing the function of 
     <literal>upgrade</literal>, also intelligently handles changing dependencies 
     with new versions of packages; <command>apt-get</command> has a "smart" conflict 
     resolution system, and it will attempt to upgrade the most important 
     packages at the expense of less important ones if necessary. 
     The <filename>/etc/apt/sources.list</filename> file contains a list of locations 
     from which to retrieve desired package files.
     See also &apt-preferences; for a mechanism for
     overriding the general settings for individual packages.</para></listitem>
     </varlistentry>

     <varlistentry><term>install</term>
     <listitem><para><literal>install</literal> is followed by one or more packages desired for 
     installation. Each package is a package name, not a fully qualified 
     filename (for instance, in a Debian GNU/Linux system, libc6 would be the 
     argument provided, not <literal>libc6_1.9.6-2.deb</literal>) All packages required 
     by the package(s) specified for installation will also be retrieved and 
     installed. The <filename>/etc/apt/sources.list</filename> file is used to locate 
     the desired packages. If a hyphen is appended to the package name (with 
     no intervening space), the identified package will be removed if it is 
     installed. Similarly a plus sign can be used to designate a package to 
     install. These latter features may be used to override decisions made by 
     apt-get's conflict resolution system.</para>

     <para>A specific version of a package can be selected for installation by 
     following the package name with an equals and the version of the package 
     to select. This will cause that version to be located and selected for
     install. Alternatively a specific distribution can be selected by 
     following the package name with a slash and the version of the 
     distribution or the Archive name (stable, testing, unstable).</para>

     <para>Both of the version selection mechanisms can downgrade packages and must
     be used with care.</para>

     <para>Finally, the &apt-preferences; mechanism allows you to
     create an alternative installation policy for
     individual packages.</para>

     <para>If no package matches the given expression and the expression contains one
     of '.', '?' or '*' then it is assumed to be a POSIX regular expression,
     and it is applied
     to all package names in the database. Any matches are then installed (or
     removed). Note that matching is done by substring so 'lo.*' matches 'how-lo'
     and 'lowest'. If this is undesired, anchor the regular expression
     with a '^' or '$' character, or create a more specific regular expression.</para></listitem>
     </varlistentry>

     <varlistentry><term>remove</term>
     <listitem><para><literal>remove</literal> is identical to <literal>install</literal> except that packages are 
     removed instead of installed. If a plus sign is appended to the package 
     name (with no intervening space), the identified package will be 
     installed instead of removed.</para></listitem>
     </varlistentry>

     <varlistentry><term>source</term>
     <listitem><para><literal>source</literal> causes <command>apt-get</command> to fetch source packages. APT 
     will examine the available packages to decide which source package to 
     fetch. It will then find and download into the current directory the 
     newest available version of that source package. Source packages are 
     tracked separately from binary packages via <literal>deb-src</literal> type lines 
     in the &sources-list; file. This probably will mean that you will not 
     get the same source as the package you have installed or as you could 
     install. If the --compile options is specified then the package will be 
     compiled to a binary .deb using dpkg-buildpackage, if --download-only is 
     specified then the source package will not be unpacked.</para>

     <para>A specific source version can be retrieved by postfixing the source name
     with an equals and then the version to fetch, similar to the mechanism
     used for the package files. This enables exact matching of the source 
     package name and version, implicitly enabling the 
     <literal>APT::Get::Only-Source</literal> option.</para>
     
     <para>Note that source packages are not tracked like binary packages, they 
     exist only in the current directory and are similar to downloading source
     tar balls.</para></listitem>
     </varlistentry>

     <varlistentry><term>build-dep</term>
     <listitem><para><literal>build-dep</literal> causes apt-get to install/remove packages in an 
     attempt to satisfy the build dependencies for a source package.</para></listitem>
     </varlistentry>

     <varlistentry><term>check</term>
     <listitem><para><literal>check</literal> is a diagnostic tool; it updates the package cache and checks 
     for broken dependencies.</para></listitem>
     </varlistentry>

     <varlistentry><term>clean</term>
     <listitem><para><literal>clean</literal> clears out the local repository of retrieved package 
     files. It removes everything but the lock file from 
     <filename>&cachedir;/archives/</filename> and 
     <filename>&cachedir;/archives/partial/</filename>. When APT is used as a 
     &dselect; method, <literal>clean</literal> is run automatically.
     Those who do not use dselect will likely want to run <literal>apt-get clean</literal>
     from time to time to free up disk space.</para></listitem>
     </varlistentry>

     <varlistentry><term>autoclean</term>
     <listitem><para>Like <literal>clean</literal>, <literal>autoclean</literal> clears out the local 
     repository of retrieved package files. The difference is that it only 
     removes package files that can no longer be downloaded, and are largely 
     useless. This allows a cache to be maintained over a long period without 
     it growing out of control. The configuration option 
     <literal>APT::Clean-Installed</literal> will prevent installed packages from being
     erased if it is set to off.</para></listitem>
     </varlistentry>
   </variablelist>
 </refsect1>
 
 <refsect1><title>options</title>
   &apt-cmdblurb;

   <variablelist>
     <varlistentry><term><option>-d</option></term><term><option>--download-only</option></term>
     <listitem><para>Download only; package files are only retrieved, not unpacked or installed.
     Configuration Item: <literal>APT::Get::Download-Only</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>-f</option></term><term><option>--fix-broken</option></term>
     <listitem><para>Fix; attempt to correct a system with broken dependencies in            
     place. This option, when used with install/remove, can omit any packages
     to permit APT to deduce a likely solution. Any Package that are specified
     must completely correct the problem. The option is sometimes necessary when 
     running APT for the first time; APT itself does not allow broken package 
     dependencies to exist on a system. It is possible that a system's 
     dependency structure can be so corrupt as to require manual intervention 
     (which usually means using &dselect; or <command>dpkg --remove</command> to eliminate some of 
     the offending packages). Use of this option together with <option>-m</option> may produce an
     error in some situations. 
     Configuration Item: <literal>APT::Get::Fix-Broken</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>-m</option></term><term><option>--ignore-missing</option></term>
     <term><option>--fix-missing</option></term>
     <listitem><para>Ignore missing packages; If packages cannot be retrieved or fail the    
     integrity check after retrieval (corrupted package files), hold back    
     those packages and handle the result. Use of this option together with  
     <option>-f</option> may produce an error in some situations. If a package is 
     selected for installation (particularly if it is mentioned on the 
     command line) and it could not be downloaded then it will be silently 
     held back.
     Configuration Item: <literal>APT::Get::Fix-Missing</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--no-download</option></term>
     <listitem><para>Disables downloading of packages. This is best used with 
     <option>--ignore-missing</option> to force APT to use only the .debs it has 
     already downloaded.
     Configuration Item: <literal>APT::Get::Download</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>-q</option></term><term><option>--quiet</option></term>
     <listitem><para>Quiet; produces output suitable for logging, omitting progress indicators.
     More q's will produce more quiet up to a maximum of 2. You can also use
     <option>-q=#</option> to set the quiet level, overriding the configuration file. 
     Note that quiet level 2 implies <option>-y</option>, you should never use -qq 
     without a no-action modifier such as -d, --print-uris or -s as APT may 
     decided to do something you did not expect.
     Configuration Item: <literal>quiet</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>-s</option></term>
                   <term><option>--simulate</option></term>
		   <term><option>--just-print</option></term>
		   <term><option>--dry-run</option></term>
		   <term><option>--recon</option></term>
		   <term><option>--no-act</option></term>
     <listitem><para>No action; perform a simulation of events that would occur but do not
     actually change the system. 
     Configuration Item: <literal>APT::Get::Simulate</literal>.</para>

     <para>Simulate prints out
     a series of lines each one representing a dpkg operation, Configure (Conf),
     Remove (Remv), Unpack (Inst). Square brackets indicate broken packages with
     and empty set of square brackets meaning breaks that are of no consequence
     (rare).</para></listitem>
     </varlistentry>

     <varlistentry><term><option>-y</option></term><term><option>--yes</option></term>
                   <term><option>--assume-yes</option></term>
     <listitem><para>Automatic yes to prompts; assume "yes" as answer to all prompts and run
     non-interactively. If an undesirable situation, such as changing a held
     package or removing an essential package occurs then <literal>apt-get</literal> 
     will abort. 
     Configuration Item: <literal>APT::Get::Assume-Yes</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>-u</option></term><term><option>--show-upgraded</option></term>
     <listitem><para>Show upgraded packages; Print out a list of all packages that are to be
     upgraded. 
     Configuration Item: <literal>APT::Get::Show-Upgraded</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>-V</option></term><term><option>--verbose-versions</option></term>
     <listitem><para>Show full versions for upgraded and installed packages.
     Configuration Item: <literal>APT::Get::Show-Versions</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>-b</option></term><term><option>--compile</option></term>
                   <term><option>--build</option></term>
     <listitem><para>Compile source packages after downloading them.
     Configuration Item: <literal>APT::Get::Compile</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--ignore-hold</option></term>
     <listitem><para>Ignore package Holds; This causes <command>apt-get</command> to ignore a hold 
     placed on a package. This may be useful in conjunction with 
     <literal>dist-upgrade</literal> to override a large number of undesired holds. 
     Configuration Item: <literal>APT::Ignore-Hold</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--no-upgrade</option></term>
     <listitem><para>Do not upgrade packages; When used in conjunction with <literal>install</literal>,
     <literal>no-upgrade</literal> will prevent packages on the command line
     from being upgraded if they are already installed.
     Configuration Item: <literal>APT::Get::Upgrade</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--force-yes</option></term>
     <listitem><para>Force yes; This is a dangerous option that will cause apt to continue 
     without prompting if it is doing something potentially harmful. It 
     should not be used except in very special situations. Using 
     <literal>force-yes</literal> can potentially destroy your system! 
     Configuration Item: <literal>APT::Get::force-yes</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--print-uris</option></term>
     <listitem><para>Instead of fetching the files to install their URIs are printed. Each
     URI will have the path, the destination file name, the size and the expected
     md5 hash. Note that the file name to write to will not always match
     the file name on the remote site! This also works with the 
     <literal>source</literal> and <literal>update</literal> commands. When used with the
     <literal>update</literal> command the MD5 and size are not included, and it is
     up to the user to decompress any compressed files.
     Configuration Item: <literal>APT::Get::Print-URIs</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--purge</option></term>
     <listitem><para>Use purge instead of remove for anything that would be removed.
     An asterisk ("*") will be displayed next to packages which are
     scheduled to be purged.
     Configuration Item: <literal>APT::Get::Purge</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--reinstall</option></term>
     <listitem><para>Re-Install packages that are already installed and at the newest version.
     Configuration Item: <literal>APT::Get::ReInstall</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--list-cleanup</option></term>
     <listitem><para>This option defaults to on, use <literal>--no-list-cleanup</literal> to turn it 
     off. When on <command>apt-get</command> will automatically manage the contents of 
     <filename>&statedir;/lists</filename> to ensure that obsolete files are erased. 
     The only  reason to turn it off is if you frequently change your source 
     list. 
     Configuration Item: <literal>APT::Get::List-Cleanup</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>-t</option></term>
                   <term><option>--target-release</option></term>
                   <term><option>--default-release</option></term>
     <listitem><para>This option controls the default input to the policy engine, it creates
     a default pin at priority 990 using the specified release string. The
     preferences file may further override this setting. In short, this option
     lets you have simple control over which distribution packages will be
     retrieved from. Some common examples might be 
     <option>-t '2.1*'</option> or <option>-t unstable</option>.
     Configuration Item: <literal>APT::Default-Release</literal>;
     see also the &apt-preferences; manual page.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--trivial-only</option></term>
     <listitem><para>
     Only perform operations that are 'trivial'. Logically this can be considered
     related to <option>--assume-yes</option>, where <option>--assume-yes</option> will answer 
     yes to any prompt, <option>--trivial-only</option> will answer no. 
     Configuration Item: <literal>APT::Get::Trivial-Only</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--no-remove</option></term>
     <listitem><para>If any packages are to be removed apt-get immediately aborts without
     prompting. 
     Configuration Item: <literal>APT::Get::Remove</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--only-source</option></term>
     <listitem><para>Only has meaning for the <literal>source</literal> command.  Indicates that the
     given source names are not to be mapped through the binary
     table.  This means that if this option is specified, the
     <literal>source</literal> command will only accept source package names as
     arguments, rather than accepting binary package names and looking
     up the corresponding source package.
     Configuration Item: <literal>APT::Get::Only-Source</literal>.</para></listitem>
     </varlistentry>

     <varlistentry><term><option>--diff-only</option></term><term><option>--tar-only</option></term>
     <listitem><para>Download only the diff or tar file of a source archive. 
     Configuration Item: <literal>APT::Get::Diff-Only</literal> and 
     <literal>APT::Get::Tar-Only</literal>.</para></listitem>
     </varlistentry>
     
     <varlistentry><term><option>--arch-only</option></term>
     <listitem><para>Only process architecture-dependent build-dependencies.
     Configuration Item: <literal>APT::Get::Arch-Only</literal>.</para></listitem>
     </varlistentry>
     
     &apt-commonoptions;
     
   </variablelist>
 </refsect1>

 <refsect1><title>Files</title>
   <variablelist>
     <varlistentry><term><filename>/etc/apt/sources.list</filename></term>
     <listitem><para>Locations to fetch packages from.
     Configuration Item: <literal>Dir::Etc::SourceList</literal>.</para></listitem>
     </varlistentry>
     
     <varlistentry><term><filename>/etc/apt/apt.conf</filename></term>
     <listitem><para>APT configuration file.
     Configuration Item: <literal>Dir::Etc::Main</literal>.</para></listitem>
     </varlistentry>
     
     <varlistentry><term><filename>/etc/apt/apt.conf.d/</filename></term>
     <listitem><para>APT configuration file fragments
     Configuration Item: <literal>Dir::Etc::Parts</literal>.</para></listitem>
     </varlistentry>
     
     <varlistentry><term><filename>/etc/apt/preferences</filename></term>
     <listitem><para>Version preferences file.
     This is where you would specify "pinning",
     i.e. a preference to get certain packages
     from a separate source
     or from a different version of a distribution.
     Configuration Item: <literal>Dir::Etc::Preferences</literal>.</para></listitem>
     </varlistentry>
     
     <varlistentry><term><filename>&cachedir;/archives/</filename></term>
     <listitem><para>Storage area for retrieved package files.
     Configuration Item: <literal>Dir::Cache::Archives</literal>.</para></listitem>
     </varlistentry>
     
     <varlistentry><term><filename>&cachedir;/archives/partial/</filename></term>
     <listitem><para>Storage area for package files in transit.
     Configuration Item: <literal>Dir::Cache::Archives</literal> (implicit partial). </para></listitem>
     </varlistentry>
     
     <varlistentry><term><filename>&statedir;/lists/</filename></term>
     <listitem><para>Storage area for state information for each package resource specified in
     &sources-list;
     Configuration Item: <literal>Dir::State::Lists</literal>.</para></listitem>
     </varlistentry>
  
     <varlistentry><term><filename>&statedir;/lists/partial/</filename></term>
     <listitem><para> Storage area for state information in transit.
     Configuration Item: <literal>Dir::State::Lists</literal> (implicit partial).</para></listitem>
     </varlistentry>     
   </variablelist>
 </refsect1>

 <refsect1><title>See Also</title>
   <para>&apt-cache;, &apt-cdrom;, &dpkg;, &dselect;, &sources-list;,
   &apt-conf;, &apt-config;,
   The APT User's guide in &docdir;, &apt-preferences;, the APT Howto.</para>
 </refsect1>

 <refsect1><title>Diagnostics</title>
   <para><command>apt-get</command> returns zero on normal operation, decimal 100 on error.</para>
 </refsect1>

 &manbugs;
 &manauthor;
 
</refentry>