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+<?xml version="1.0" encoding="utf-8" standalone="no"?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
+
+<!ENTITY % aptent SYSTEM "apt.ent">
+%aptent;
+
+]>
+
+<refentry>
+ &apt-docinfo;
+
+ <refmeta>
+ <refentrytitle>apt.conf</refentrytitle>
+ <manvolnum>5</manvolnum>
+ </refmeta>
+
+ <!-- Man page title -->
+ <refnamediv>
+ <refname>apt.conf</refname>
+ <refpurpose>Configuration file for APT</refpurpose>
+ </refnamediv>
+
+ <refsect1><title>Description</title>
+ <para><filename>apt.conf</filename> is the main configuration file for the APT suite of
+ tools, all tools make use of the configuration file and a common command line
+ parser to provide a uniform environment. When an APT tool starts up it will
+ read the configuration specified by the <envar>APT_CONFIG</envar> environment
+ variable (if any) and then read the files in <literal>Dir::Etc::Parts</literal>
+ then read the main configuration file specified by
+ <literal>Dir::Etc::main</literal> then finally apply the
+ command line options to override the configuration directives, possibly
+ loading even more config files.</para>
+
+ <para>The configuration file is organized in a tree with options organized into
+ functional groups. option specification is given with a double colon
+ notation, for instance <literal>APT::Get::Assume-Yes</literal> is an option within
+ the APT tool group, for the Get tool. options do not inherit from their
+ parent groups.</para>
+
+ <para>Syntacticly the configuration language is modeled after what the ISC tools
+ such as bind and dhcp use. Lines starting with
+ <literal>//</literal> are treated as comments (ignored).
+ Each line is of the form
+ <literal>APT::Get::Assume-Yes "true";</literal> The trailing
+ semicolon is required and the quotes are optional. A new scope can be
+ opened with curly braces, like:</para>
+
+<informalexample><programlisting>
+APT {
+ Get {
+ Assume-Yes "true";
+ Fix-Broken "true";
+ };
+};
+</programlisting></informalexample>
+
+ <para>with newlines placed to make it more readable. Lists can be created by
+ opening a scope and including a single word enclosed in quotes followed by a
+ semicolon. Multiple entries can be included, each separated by a semicolon.</para>
+
+<informalexample><programlisting>
+DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt";};
+</programlisting></informalexample>
+
+ <para>In general the sample configuration file in
+ <filename>&docdir;examples/apt.conf</filename> &configureindex;
+ is a good guide for how it should look.</para>
+
+ <para>Two specials are allowed, <literal>#include</literal> and <literal>#clear</literal>
+ <literal>#include</literal> will include the given file, unless the filename
+ ends in a slash, then the whole directory is included.
+ <literal>#clear</literal> is used to erase a list of names.</para>
+
+ <para>All of the APT tools take a -o option which allows an arbitrary configuration
+ directive to be specified on the command line. The syntax is a full option
+ name (<literal>APT::Get::Assume-Yes</literal> for instance) followed by an equals
+ sign then the new value of the option. Lists can be appended too by adding
+ a trailing :: to the list name.</para>
+ </refsect1>
+
+ <refsect1><title>The APT Group</title>
+ <para>This group of options controls general APT behavior as well as holding the
+ options for all of the tools.</para>
+
+ <variablelist>
+ <varlistentry><term>Architecture</term>
+ <listitem><para>System Architecture; sets the architecture to use when fetching files and
+ parsing package lists. The internal default is the architecture apt was
+ compiled for.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Ignore-Hold</term>
+ <listitem><para>Ignore Held packages; This global option causes the problem resolver to
+ ignore held packages in its decision making.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Clean-Installed</term>
+ <listitem><para>Defaults to on. When turned on the autoclean feature will remove any packages
+ which can no longer be downloaded from the cache. If turned off then
+ packages that are locally installed are also excluded from cleaning - but
+ note that APT provides no direct means to reinstall them.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Immediate-Configure</term>
+ <listitem><para>Disable Immediate Configuration; This dangerous option disables some
+ of APT's ordering code to cause it to make fewer dpkg calls. Doing
+ so may be necessary on some extremely slow single user systems but
+ is very dangerous and may cause package install scripts to fail or worse.
+ Use at your own risk.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Force-LoopBreak</term>
+ <listitem><para>Never Enable this option unless you -really- know what you are doing. It
+ permits APT to temporarily remove an essential package to break a
+ Conflicts/Conflicts or Conflicts/Pre-Depend loop between two essential
+ packages. SUCH A LOOP SHOULD NEVER EXIST AND IS A GRAVE BUG. This option
+ will work if the essential packages are not tar, gzip, libc, dpkg, bash or
+ anything that those packages depend on.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Cache-Limit</term>
+ <listitem><para>APT uses a fixed size memory mapped cache file to store the 'available'
+ information. This sets the size of that cache.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Build-Essential</term>
+ <listitem><para>Defines which package(s) are considered essential build dependencies.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Get</term>
+ <listitem><para>The Get subsection controls the &apt-get; tool, please see its
+ documentation for more information about the options here.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Cache</term>
+ <listitem><para>The Cache subsection controls the &apt-cache; tool, please see its
+ documentation for more information about the options here.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>CDROM</term>
+ <listitem><para>The CDROM subsection controls the &apt-cdrom; tool, please see its
+ documentation for more information about the options here.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1><title>The Acquire Group</title>
+ <para>The <literal>Acquire</literal> group of options controls the download of packages
+ and the URI handlers.
+
+ <variablelist>
+ <varlistentry><term>Queue-Mode</term>
+ <listitem><para>Queuing mode; <literal>Queue-Mode</literal> can be one of <literal>host</literal> or
+ <literal>access</literal> which determines how APT parallelizes outgoing
+ connections. <literal>host</literal> means that one connection per target host
+ will be opened, <literal>access</literal> means that one connection per URI type
+ will be opened.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Retries</term>
+ <listitem><para>Number of retries to perform. If this is non-zero APT will retry failed
+ files the given number of times.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Source-Symlinks</term>
+ <listitem><para>Use symlinks for source archives. If set to true then source archives will
+ be symlinked when possible instead of copying. True is the default.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>http</term>
+ <listitem><para>HTTP URIs; http::Proxy is the default http proxy to use. It is in the
+ standard form of <literal>http://[[user][:pass]@]host[:port]/</literal>. Per
+ host proxies can also be specified by using the form
+ <literal>http::Proxy::&lt;host&gt;</literal> with the special keyword <literal>DIRECT</literal>
+ meaning to use no proxies. The <envar>http_proxy</envar> environment variable
+ will override all settings.</para>
+
+ <para>Three settings are provided for cache control with HTTP/1.1 compliant
+ proxy caches. <literal>No-Cache</literal> tells the proxy to not use its cached
+ response under any circumstances, <literal>Max-Age</literal> is sent only for
+ index files and tells the cache to refresh its object if it is older than
+ the given number of seconds. Debian updates its index files daily so the
+ default is 1 day. <literal>No-Store</literal> specifies that the cache should never
+ store this request, it is only set for archive files. This may be useful
+ to prevent polluting a proxy cache with very large .deb files. Note:
+ Squid 2.0.2 does not support any of these options.</para>
+
+ <para>The option <literal>timeout</literal> sets the timeout timer used by the method,
+ this applies to all things including connection timeout and data timeout.</para>
+
+ <para>One setting is provided to control the pipeline depth in cases where the
+ remote server is not RFC conforming or buggy (such as Squid 2.0.2)
+ <literal>Acquire::http::Pipeline-Depth</literal> can be a value from 0 to 5
+ indicating how many outstanding requests APT should send. A value of
+ zero MUST be specified if the remote host does not properly linger
+ on TCP connections - otherwise data corruption will occur. Hosts which
+ require this are in violation of RFC 2068.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>ftp</term>
+ <listitem><para>FTP URIs; ftp::Proxy is the default proxy server to use. It is in the
+ standard form of <literal>ftp://[[user][:pass]@]host[:port]/</literal> and is
+ overridden by the <envar>ftp_proxy</envar> environment variable. To use a ftp
+ proxy you will have to set the <literal>ftp::ProxyLogin</literal> script in the
+ configuration file. This entry specifies the commands to send to tell
+ the proxy server what to connect to. Please see
+ &configureindex; for an example of
+ how to do this. The subsitution variables available are
+ <literal>$(PROXY_USER)</literal> <literal>$(PROXY_PASS)</literal> <literal>$(SITE_USER)</literal>
+ <literal>$(SITE_PASS)</literal> <literal>$(SITE)</literal> and <literal>$(SITE_PORT)</literal>
+ Each is taken from it's respective URI component.</para>
+
+ <para>The option <literal>timeout</literal> sets the timeout timer used by the method,
+ this applies to all things including connection timeout and data timeout.</para>
+
+ <para>Several settings are provided to control passive mode. Generally it is
+ safe to leave passive mode on, it works in nearly every environment.
+ However some situations require that passive mode be disabled and port
+ mode ftp used instead. This can be done globally, for connections that
+ go through a proxy or for a specific host (See the sample config file
+ for examples).</para>
+
+ <para>It is possible to proxy FTP over HTTP by setting the <envar>ftp_proxy</envar>
+ environment variable to a http url - see the discussion of the http method
+ above for syntax. You cannot set this in the configuration file and it is
+ not recommended to use FTP over HTTP due to its low efficiency.</para>
+
+ <para>The setting <literal>ForceExtended</literal> controls the use of RFC2428
+ <literal>EPSV</literal> and <literal>EPRT</literal> commands. The defaut is false, which means
+ these commands are only used if the control connection is IPv6. Setting this
+ to true forces their use even on IPv4 connections. Note that most FTP servers
+ do not support RFC2428.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>cdrom</term>
+ <listitem><para>CDROM URIs; the only setting for CDROM URIs is the mount point,
+ <literal>cdrom::Mount</literal> which must be the mount point for the CDROM drive
+ as specified in <filename>/etc/fstab</filename>. It is possible to provide
+ alternate mount and unmount commands if your mount point cannot be listed
+ in the fstab (such as an SMB mount and old mount packages). The syntax
+ is to put <literallayout>"/cdrom/"::Mount "foo";</literallayout> within
+ the cdrom block. It is important to have the trailing slash. Unmount
+ commands can be specified using UMount.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </refsect1>
+
+ <refsect1><title>Directories</title>
+
+ <para>The <literal>Dir::State</literal> section has directories that pertain to local
+ state information. <literal>lists</literal> is the directory to place downloaded
+ package lists in and <literal>status</literal> is the name of the dpkg status file.
+ <literal>preferences</literal> is the name of the APT preferences file.
+ <literal>Dir::State</literal> contains the default directory to prefix on all sub
+ items if they do not start with <filename>/</filename> or <filename>./</filename>.</para>
+
+ <para><literal>Dir::Cache</literal> contains locations pertaining to local cache
+ information, such as the two package caches <literal>srcpkgcache</literal> and
+ <literal>pkgcache</literal> as well as the location to place downloaded archives,
+ <literal>Dir::Cache::archives</literal>. Generation of caches can be turned off
+ by setting their names to be blank. This will slow down startup but
+ save disk space. It is probably prefered to turn off the pkgcache rather
+ than the srcpkgcache. Like <literal>Dir::State</literal> the default
+ directory is contained in <literal>Dir::Cache</literal></para>
+
+ <para><literal>Dir::Etc</literal> contains the location of configuration files,
+ <literal>sourcelist</literal> gives the location of the sourcelist and
+ <literal>main</literal> is the default configuration file (setting has no effect,
+ unless it is done from the config file specified by
+ <envar>APT_CONFIG</envar>.</para>
+
+ <para>The <literal>Dir::Parts</literal> setting reads in all the config fragments in
+ lexical order from the directory specified. After this is done then the
+ main config file is loaded.</para>
+
+ <para>Binary programs are pointed to by <literal>Dir::Bin</literal>. <literal>Dir::Bin::Methods</literal>
+ specifies the location of the method handlers and <literal>gzip</literal>,
+ <literal>dpkg</literal>, <literal>apt-get</literal> <literal>dpkg-source</literal>
+ <literal>dpkg-buildpackage</literal> and <literal>apt-cache</literal> specify the location
+ of the respective programs.</para>
+ </refsect1>
+
+ <refsect1><title>APT in DSelect</title>
+ <para>
+ When APT is used as a &dselect; method several configuration directives
+ control the default behaviour. These are in the <literal>DSelect</literal> section.</para>
+
+ <variablelist>
+ <varlistentry><term>Clean</term>
+ <listitem><para>Cache Clean mode; this value may be one of always, prompt, auto,
+ pre-auto and never. always and prompt will remove all packages from
+ the cache after upgrading, prompt (the default) does so conditionally.
+ auto removes only those packages which are no longer downloadable
+ (replaced with a new version for instance). pre-auto performs this
+ action before downloading new packages.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>options</term>
+ <listitem><para>The contents of this variable is passed to &apt-get; as command line
+ options when it is run for the install phase.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Updateoptions</term>
+ <listitem><para>The contents of this variable is passed to &apt-get; as command line
+ options when it is run for the update phase.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>PromptAfterUpdate</term>
+ <listitem><para>If true the [U]pdate operation in &dselect; will always prompt to continue.
+ The default is to prompt only on error.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1><title>How APT calls dpkg</title>
+ <para>Several configuration directives control how APT invokes &dpkg;. These are
+ in the <literal>DPkg</literal> section.</para>
+
+ <variablelist>
+ <varlistentry><term>options</term>
+ <listitem><para>This is a list of options to pass to dpkg. The options must be specified
+ using the list notation and each list item is passed as a single argument
+ to &dpkg;.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Pre-Invoke</term><term>Post-Invoke</term>
+ <listitem><para>This is a list of shell commands to run before/after invoking &dpkg;.
+ Like <literal>options</literal> this must be specified in list notation. The
+ commands are invoked in order using <filename>/bin/sh</filename>, should any
+ fail APT will abort.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Pre-Install-Pkgs</term>
+ <listitem><para>This is a list of shell commands to run before invoking dpkg. Like
+ <literal>options</literal> this must be specified in list notation. The commands
+ are invoked in order using <filename>/bin/sh</filename>, should any fail APT
+ will abort. APT will pass to the commands on standard input the
+ filenames of all .deb files it is going to install, one per line.</para>
+
+ <para>Version 2 of this protocol dumps more information, including the
+ protocol version, the APT configuration space and the packages, files
+ and versions being changed. Version 2 is enabled by setting
+ <literal>DPkg::Tools::options::cmd::Version</literal> to 2. <literal>cmd</literal> is a
+ command given to <literal>Pre-Install-Pkgs</literal>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Run-Directory</term>
+ <listitem><para>APT chdirs to this directory before invoking dpkg, the default is
+ <filename>/</filename>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry><term>Build-options</term>
+ <listitem><para>These options are passed to &dpkg-buildpackage; when compiling packages,
+ the default is to disable signing and produce all binaries.</para></listitem>
+ </varlistentry>
+ </variablelist>
+ </refsect1>
+
+ <refsect1><title>Debug options</title>
+ <para>Most of the options in the <literal>debug</literal> section are not interesting to
+ the normal user, however <literal>Debug::pkgProblemResolver</literal> shows
+ interesting output about the decisions dist-upgrade makes.
+ <literal>Debug::NoLocking</literal> disables file locking so APT can do some
+ operations as non-root and <literal>Debug::pkgDPkgPM</literal> will print out the
+ command line for each dpkg invokation. <literal>Debug::IdentCdrom</literal> will
+ disable the inclusion of statfs data in CDROM IDs.</para>
+ </refsect1>
+
+ <refsect1><title>Examples</title>
+ <para>&configureindex; contains a
+ sample configuration file showing the default values for all possible
+ options.</para>
+ </refsect1>
+
+ <refsect1><title>Files</title>
+ <para><filename>/etc/apt/apt.conf</filename></para>
+ </refsect1>
+
+ <refsect1><title>See Also</title>
+ <para>&apt-cache;, &apt-config;<!-- ? reading apt.conf -->, &apt-preferences;.</para>
+ </refsect1>
+
+ &manbugs;
+ &manauthor;
+
+</refentry>
+