doc/apt.conf.5.xml

   1 <?xml version="1.0" encoding="utf-8" standalone="no"?>
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
   4
   5 <!ENTITY % aptent SYSTEM "apt.ent">
   6 %aptent;
   7
   8 ]>
   9
  10 <refentry>
  11
  12  <refentryinfo>
  13    &apt-author.jgunthorpe;
  14    &apt-author.team;
  15    <author>
  16      <firstname>Daniel</firstname>
  17      <surname>Burrows</surname>
  18      <contrib>Initial documentation of Debug::*.</contrib>
  19      <email>dburrows@debian.org</email>
  20    </author>
  21    &apt-email;
  22    &apt-product;
  23    <!-- The last update date -->
  24    <date>18 September 2009</date>
  25  </refentryinfo>
  26
  27  <refmeta>
  28    <refentrytitle>apt.conf</refentrytitle>
  29    <manvolnum>5</manvolnum>
  30    <refmiscinfo class="manual">APT</refmiscinfo>
  31  </refmeta>
  32
  33  <!-- Man page title -->
  34  <refnamediv>
  35     <refname>apt.conf</refname>
  36     <refpurpose>Configuration file for APT</refpurpose>
  37  </refnamediv>
  38
  39  <refsect1><title>Description</title>
  40    <para><filename>apt.conf</filename> is the main configuration file for the APT suite of
  41    tools, all tools make use of the configuration file and a common command line
  42    parser to provide a uniform environment. When an APT tool starts up it will
  43    read the configuration specified by the <envar>APT_CONFIG</envar> environment
  44    variable (if any) and then read the files in <literal>Dir::Etc::Parts</literal>
  45    then read the main configuration file specified by
  46    <literal>Dir::Etc::main</literal> then finally apply the
  47    command line options to override the configuration directives, possibly
  48    loading even more config files.</para>
  49
  50    <para>The configuration file is organized in a tree with options organized into
  51    functional groups. option specification is given with a double colon
  52    notation, for instance <literal>APT::Get::Assume-Yes</literal> is an option within
  53    the APT tool group, for the Get tool. options do not inherit from their
  54    parent groups.</para>
  55
  56    <para>Syntactically the configuration language is modeled after what the ISC tools
  57    such as bind and dhcp use. Lines starting with
  58    <literal>//</literal> are treated as comments (ignored), as well as all text
  59    between <literal>/*</literal> and <literal>*/</literal>, just like C/C++ comments.
  60    Each line is of the form
  61    <literal>APT::Get::Assume-Yes "true";</literal> The trailing
  62    semicolon is required and the quotes are optional. A new scope can be
  63    opened with curly braces, like:</para>
  64
  65 <informalexample><programlisting>
  66 APT {
  67   Get {
  68     Assume-Yes "true";
  69     Fix-Broken "true";
  70   };
  71 };
  72 </programlisting></informalexample>
  73
  74    <para>with newlines placed to make it more readable. Lists can be created by
  75    opening a scope and including a single string enclosed in quotes followed by a
  76    semicolon. Multiple entries can be included, each separated by a semicolon.</para>
  77
  78 <informalexample><programlisting>
  79 DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt";};
  80 </programlisting></informalexample>
  81
  82    <para>In general the sample configuration file in
  83    <filename>&docdir;examples/apt.conf</filename> &configureindex;
  84    is a good guide for how it should look.</para>
  85
  86    <para>The names of the configuration items are not case-sensitive. So in the previous example
  87    you could use <literal>dpkg::pre-install-pkgs</literal>.</para>
  88
  89    <para>Two specials are allowed, <literal>#include</literal> and <literal>#clear</literal>
  90    <literal>#include</literal> will include the given file, unless the filename
  91    ends in a slash, then the whole directory is included.
  92    <literal>#clear</literal> is used to erase a part of the configuration tree. The
  93    specified element and all its descendants are erased.</para>
  94
  95    <para>All of the APT tools take a -o option which allows an arbitrary configuration
  96    directive to be specified on the command line. The syntax is a full option
  97    name (<literal>APT::Get::Assume-Yes</literal> for instance) followed by an equals
  98    sign then the new value of the option. Lists can be appended too by adding
  99    a trailing :: to the list name.</para>
 100  </refsect1>
 101
 102  <refsect1><title>The APT Group</title>
 103    <para>This group of options controls general APT behavior as well as holding the
 104    options for all of the tools.</para>
 105
 106    <variablelist>
 107      <varlistentry><term>Architecture</term>
 108      <listitem><para>System Architecture; sets the architecture to use when fetching files and
 109      parsing package lists. The internal default is the architecture apt was
 110      compiled for.</para></listitem>
 111      </varlistentry>
 112
 113      <varlistentry><term>Default-Release</term>
 114          <listitem><para>Default release to install packages from if more than one
 115          version available. Contains release name, codename or release version. Examples: 'stable', 'testing', 'unstable', 'lenny', 'squeeze', '4.0', '5.0*'. See also &apt-preferences;.</para></listitem>
 116      </varlistentry>
 117
 118      <varlistentry><term>Ignore-Hold</term>
 119      <listitem><para>Ignore Held packages; This global option causes the problem resolver to
 120      ignore held packages in its decision making.</para></listitem>
 121      </varlistentry>
 122
 123      <varlistentry><term>Clean-Installed</term>
 124      <listitem><para>Defaults to on. When turned on the autoclean feature will remove any packages
 125      which can no longer be downloaded from the cache. If turned off then
 126      packages that are locally installed are also excluded from cleaning - but
 127      note that APT provides no direct means to reinstall them.</para></listitem>
 128      </varlistentry>
 129
 130      <varlistentry><term>Immediate-Configure</term>
 131      <listitem><para>Disable Immediate Configuration; This dangerous option disables some
 132      of APT's ordering code to cause it to make fewer dpkg calls. Doing
 133      so may be necessary on some extremely slow single user systems but
 134      is very dangerous and may cause package install scripts to fail or worse.
 135      Use at your own risk.</para></listitem>
 136      </varlistentry>
 137
 138      <varlistentry><term>Force-LoopBreak</term>
 139      <listitem><para>Never Enable this option unless you -really- know what you are doing. It
 140      permits APT to temporarily remove an essential package to break a
 141      Conflicts/Conflicts or Conflicts/Pre-Depend loop between two essential
 142      packages. SUCH A LOOP SHOULD NEVER EXIST AND IS A GRAVE BUG. This option
 143      will work if the essential packages are not tar, gzip, libc, dpkg, bash or
 144      anything that those packages depend on.</para></listitem>
 145      </varlistentry>
 146
 147      <varlistentry><term>Cache-Limit</term>
 148      <listitem><para>APT uses a fixed size memory mapped cache file to store the 'available'
 149      information. This sets the size of that cache (in bytes).</para></listitem>
 150      </varlistentry>
 151
 152      <varlistentry><term>Build-Essential</term>
 153      <listitem><para>Defines which package(s) are considered essential build dependencies.</para></listitem>
 154      </varlistentry>
 155
 156      <varlistentry><term>Get</term>
 157      <listitem><para>The Get subsection controls the &apt-get; tool, please see its
 158      documentation for more information about the options here.</para></listitem>
 159      </varlistentry>
 160
 161      <varlistentry><term>Cache</term>
 162      <listitem><para>The Cache subsection controls the &apt-cache; tool, please see its
 163      documentation for more information about the options here.</para></listitem>
 164      </varlistentry>
 165
 166      <varlistentry><term>CDROM</term>
 167      <listitem><para>The CDROM subsection controls the &apt-cdrom; tool, please see its
 168      documentation for more information about the options here.</para></listitem>
 169      </varlistentry>
 170    </variablelist>
 171  </refsect1>
 172
 173  <refsect1><title>The Acquire Group</title>
 174    <para>The <literal>Acquire</literal> group of options controls the download of packages
 175    and the URI handlers.
 176
 177    <variablelist>
 178      <varlistentry><term>PDiffs</term>
 179          <listitem><para>Try to download deltas called <literal>PDiffs</literal> for
 180          Packages or Sources files instead of downloading whole ones. True
 181          by default.</para></listitem>
 182      </varlistentry>
 183
 184      <varlistentry><term>Queue-Mode</term>
 185      <listitem><para>Queuing mode; <literal>Queue-Mode</literal> can be one of <literal>host</literal> or
 186      <literal>access</literal> which determines how  APT parallelizes outgoing
 187      connections. <literal>host</literal> means that one connection per target host
 188      will be opened, <literal>access</literal> means that one connection per URI type
 189      will be opened.</para></listitem>
 190      </varlistentry>
 191
 192      <varlistentry><term>Retries</term>
 193      <listitem><para>Number of retries to perform. If this is non-zero APT will retry failed
 194      files the given number of times.</para></listitem>
 195      </varlistentry>
 196
 197      <varlistentry><term>Source-Symlinks</term>
 198      <listitem><para>Use symlinks for source archives. If set to true then source archives will
 199      be symlinked when possible instead of copying. True is the default.</para></listitem>
 200      </varlistentry>
 201
 202      <varlistentry><term>http</term>
 203      <listitem><para>HTTP URIs; http::Proxy is the default http proxy to use. It is in the
 204      standard form of <literal>http://[[user][:pass]@]host[:port]/</literal>. Per
 205      host proxies can also be specified by using the form
 206      <literal>http::Proxy::&lt;host&gt;</literal> with the special keyword <literal>DIRECT</literal>
 207          meaning to use no proxies. If no one of the above settings is specified,
 208          <envar>http_proxy</envar> environment variable
 209          will be used.</para>
 210
 211      <para>Three settings are provided for cache control with HTTP/1.1 compliant
 212      proxy caches. <literal>No-Cache</literal> tells the proxy to not use its cached
 213      response under any circumstances, <literal>Max-Age</literal> is sent only for
 214      index files and tells the cache to refresh its object if it is older than
 215      the given number of seconds. Debian updates its index files daily so the
 216      default is 1 day. <literal>No-Store</literal> specifies that the cache should never
 217      store this request, it is only set for archive files. This may be useful
 218      to prevent polluting a proxy cache with very large .deb files. Note:
 219      Squid 2.0.2 does not support any of these options.</para>
 220
 221      <para>The option <literal>timeout</literal> sets the timeout timer used by the method,
 222      this applies to all things including connection timeout and data timeout.</para>
 223
 224      <para>One setting is provided to control the pipeline depth in cases where the
 225      remote server is not RFC conforming or buggy (such as Squid 2.0.2)
 226      <literal>Acquire::http::Pipeline-Depth</literal> can be a value from 0 to 5
 227      indicating how many outstanding requests APT should send. A value of
 228      zero MUST be specified if the remote host does not properly linger
 229      on TCP connections - otherwise data corruption will occur. Hosts which
 230      require this are in violation of RFC 2068.</para></listitem>
 231      </varlistentry>
 232
 233      <varlistentry><term>https</term>
 234          <listitem><para>HTTPS URIs. Cache-control and proxy options are the same as for
 235          <literal>http</literal> method.
 236          <literal>Pipeline-Depth</literal> option is not supported yet.</para>
 237
 238          <para><literal>CaInfo</literal> suboption specifies place of file that
 239          holds info about trusted certificates.
 240          <literal>&lt;host&gt;::CaInfo</literal> is corresponding per-host option.
 241          <literal>Verify-Peer</literal> boolean suboption determines whether verify
 242          server's host certificate against trusted certificates or not.
 243          <literal>&lt;host&gt;::Verify-Peer</literal> is corresponding per-host option.
 244          <literal>Verify-Host</literal> boolean suboption determines whether verify
 245          server's hostname or not.
 246          <literal>&lt;host&gt;::Verify-Host</literal> is corresponding per-host option.
 247          <literal>SslCert</literal> determines what certificate to use for client
 248          authentication. <literal>&lt;host&gt;::SslCert</literal> is corresponding per-host option.
 249          <literal>SslKey</literal> determines what private key to use for client
 250          authentication. <literal>&lt;host&gt;::SslKey</literal> is corresponding per-host option.
 251          <literal>SslForceVersion</literal> overrides default SSL version to use.
 252          Can contain 'TLSv1' or 'SSLv3' string.
 253          <literal>&lt;host&gt;::SslForceVersion</literal> is corresponding per-host option.
 254          </para></listitem></varlistentry>
 255
 256      <varlistentry><term>ftp</term>
 257      <listitem><para>FTP URIs; ftp::Proxy is the default ftp proxy to use. It is in the
 258      standard form of <literal>ftp://[[user][:pass]@]host[:port]/</literal>. Per
 259      host proxies can also be specified by using the form
 260      <literal>ftp::Proxy::&lt;host&gt;</literal> with the special keyword <literal>DIRECT</literal>
 261          meaning to use no proxies. If no one of the above settings is specified,
 262          <envar>ftp_proxy</envar> environment variable
 263          will be used. To use a ftp
 264      proxy you will have to set the <literal>ftp::ProxyLogin</literal> script in the
 265      configuration file. This entry specifies the commands to send to tell
 266      the proxy server what to connect to. Please see
 267      &configureindex; for an example of
 268      how to do this. The substitution variables available are
 269      <literal>$(PROXY_USER)</literal> <literal>$(PROXY_PASS)</literal> <literal>$(SITE_USER)</literal>
 270      <literal>$(SITE_PASS)</literal> <literal>$(SITE)</literal> and <literal>$(SITE_PORT)</literal>
 271      Each is taken from it's respective URI component.</para>
 272
 273      <para>The option <literal>timeout</literal> sets the timeout timer used by the method,
 274      this applies to all things including connection timeout and data timeout.</para>
 275
 276      <para>Several settings are provided to control passive mode. Generally it is
 277      safe to leave passive mode on, it works in nearly every environment.
 278      However some situations require that passive mode be disabled and port
 279      mode ftp used instead. This can be done globally, for connections that
 280      go through a proxy or for a specific host (See the sample config file
 281      for examples).</para>
 282
 283      <para>It is possible to proxy FTP over HTTP by setting the <envar>ftp_proxy</envar>
 284      environment variable to a http url - see the discussion of the http method
 285      above for syntax. You cannot set this in the configuration file and it is
 286      not recommended to use FTP over HTTP due to its low efficiency.</para>
 287
 288      <para>The setting <literal>ForceExtended</literal> controls the use of RFC2428
 289      <literal>EPSV</literal> and <literal>EPRT</literal> commands. The default is false, which means
 290      these commands are only used if the control connection is IPv6. Setting this
 291      to true forces their use even on IPv4 connections. Note that most FTP servers
 292      do not support RFC2428.</para></listitem>
 293      </varlistentry>
 294
 295      <varlistentry><term>cdrom</term>
 296      <listitem><para>CDROM URIs; the only setting for CDROM URIs is the mount point,
 297      <literal>cdrom::Mount</literal> which must be the mount point for the CDROM drive
 298      as specified in <filename>/etc/fstab</filename>. It is possible to provide
 299      alternate mount and unmount commands if your mount point cannot be listed
 300      in the fstab (such as an SMB mount and old mount packages). The syntax
 301      is to put <literallayout>"/cdrom/"::Mount "foo";</literallayout> within
 302      the cdrom block. It is important to have the trailing slash. Unmount
 303      commands can be specified using UMount.</para></listitem>
 304      </varlistentry>
 305
 306      <varlistentry><term>gpgv</term>
 307      <listitem><para>GPGV URIs; the only option for GPGV URIs is the option to pass additional parameters to gpgv.
 308      <literal>gpgv::Options</literal> Additional options passed to gpgv.
 309      </para></listitem>
 310      </varlistentry>
 311
 312      <varlistentry><term>CompressionTypes</term>
 313      <listitem><para>List of compression types which are understood by the acquire methods.
 314      Files like <filename>Packages</filename> can be available in various compression formats.
 315      Per default the acquire methods can decompress <command>bzip2</command>, <command>lzma</command>
 316      and <command>gzip</command> compressed files, with this setting more formats can be added
 317      on the fly or the used method can be changed. The syntax for this is:
 318      <synopsis>Acquire::CompressionTypes::<replaceable>FileExtension</replaceable> "<replaceable>Methodname</replaceable>";</synopsis>
 319      </para><para>Also the <literal>Order</literal> subgroup can be used to define in which order
 320      the acquire system will try to download the compressed files. The acquire system will try the first
 321      and proceed with the next compression type in this list on error, so to prefer one over the other type
 322      simple add the preferred type at first - not already added default types will be added at run time
 323      to the end of the list, so e.g. <synopsis>Acquire::CompressionTypes::Order:: "gz";</synopsis> can
 324      be used to prefer <command>gzip</command> compressed files over <command>bzip2</command> and <command>lzma</command>.
 325      If <command>lzma</command> should be preferred over <command>gzip</command> and <command>bzip2</command> the
 326      configure setting should look like this <synopsis>Acquire::CompressionTypes::Order { "lzma"; "gz"; };</synopsis>
 327      It is not needed to add <literal>bz2</literal> explicit to the list as it will be added automatic.</para>
 328      <para>Note that at run time the <literal>Dir::Bin::<replaceable>Methodname</replaceable></literal> will
 329      be checked: If this setting exists the method will only be used if this file exists, e.g. for
 330      the bzip2 method (the inbuilt) setting is <literallayout>Dir::Bin::bzip2 "/bin/bzip2";</literallayout>
 331      Note also that list entries specified on the commandline will be added at the end of the list
 332      specified in the configuration files, but before the default entries. To prefer a type in this case
 333      over the ones specified in in the configuration files you can set the option direct - not in list style.
 334      This will not override the defined list, it will only prefix the list with this type.</para>
 335      <para>While it is possible to add an empty compression type to the order list, but APT in its current
 336      version doesn't understand it correctly and will display many warnings about not downloaded files -
 337      these warnings are most of the time false negatives. Future versions will maybe include a way to
 338      really prefer uncompressed files to support the usage of local mirrors.</para></listitem>
 339      </varlistentry>
 340    </variablelist>
 341   </para>
 342  </refsect1>
 343
 344  <refsect1><title>Directories</title>
 345
 346    <para>The <literal>Dir::State</literal> section has directories that pertain to local
 347    state information. <literal>lists</literal> is the directory to place downloaded
 348    package lists in and <literal>status</literal> is the name of the dpkg status file.
 349    <literal>preferences</literal> is the name of the APT preferences file.
 350    <literal>Dir::State</literal> contains the default directory to prefix on all sub
 351    items if they do not start with <filename>/</filename> or <filename>./</filename>.</para>
 352
 353    <para><literal>Dir::Cache</literal> contains locations pertaining to local cache
 354    information, such as the two package caches <literal>srcpkgcache</literal> and
 355    <literal>pkgcache</literal> as well as the location to place downloaded archives,
 356    <literal>Dir::Cache::archives</literal>. Generation of caches can be turned off
 357    by setting their names to be blank. This will slow down startup but
 358    save disk space. It is probably preferred to turn off the pkgcache rather
 359    than the srcpkgcache. Like <literal>Dir::State</literal> the default
 360    directory is contained in <literal>Dir::Cache</literal></para>
 361
 362    <para><literal>Dir::Etc</literal> contains the location of configuration files,
 363    <literal>sourcelist</literal> gives the location of the sourcelist and
 364    <literal>main</literal> is the default configuration file (setting has no effect,
 365    unless it is done from the config file specified by
 366    <envar>APT_CONFIG</envar>).</para>
 367
 368    <para>The <literal>Dir::Parts</literal> setting reads in all the config fragments in
 369    lexical order from the directory specified. After this is done then the
 370    main config file is loaded.</para>
 371
 372    <para>Binary programs are pointed to by <literal>Dir::Bin</literal>. <literal>Dir::Bin::Methods</literal>
 373    specifies the location of the method handlers and <literal>gzip</literal>,
 374    <literal>bzip2</literal>, <literal>lzma</literal>,
 375    <literal>dpkg</literal>, <literal>apt-get</literal> <literal>dpkg-source</literal>
 376    <literal>dpkg-buildpackage</literal> and <literal>apt-cache</literal> specify the location
 377    of the respective programs.</para>
 378
 379    <para>
 380      The configuration item <literal>RootDir</literal> has a special
 381      meaning.  If set, all paths in <literal>Dir::</literal> will be
 382      relative to <literal>RootDir</literal>, <emphasis>even paths that
 383      are specified absolutely</emphasis>.  So, for instance, if
 384      <literal>RootDir</literal> is set to
 385      <filename>/tmp/staging</filename> and
 386      <literal>Dir::State::status</literal> is set to
 387      <filename>/var/lib/dpkg/status</filename>, then the status file
 388      will be looked up in
 389      <filename>/tmp/staging/var/lib/dpkg/status</filename>.
 390    </para>
 391  </refsect1>
 392
 393  <refsect1><title>APT in DSelect</title>
 394    <para>
 395    When APT is used as a &dselect; method several configuration directives
 396    control the default behaviour. These are in the <literal>DSelect</literal> section.</para>
 397
 398    <variablelist>
 399      <varlistentry><term>Clean</term>
 400      <listitem><para>Cache Clean mode; this value may be one of always, prompt, auto,
 401      pre-auto and never.  always and prompt will remove all packages from
 402      the cache after upgrading, prompt (the default) does so conditionally.
 403      auto removes only those packages which are no longer downloadable
 404      (replaced with a new version for instance).  pre-auto performs this
 405      action before downloading new packages.</para></listitem>
 406      </varlistentry>
 407
 408      <varlistentry><term>options</term>
 409      <listitem><para>The contents of this variable is passed to &apt-get; as command line
 410      options when it is run for the install phase.</para></listitem>
 411      </varlistentry>
 412
 413      <varlistentry><term>Updateoptions</term>
 414      <listitem><para>The contents of this variable is passed to &apt-get; as command line
 415      options when it is run for the update phase.</para></listitem>
 416      </varlistentry>
 417
 418      <varlistentry><term>PromptAfterUpdate</term>
 419      <listitem><para>If true the [U]pdate operation in &dselect; will always prompt to continue.
 420      The default is to prompt only on error.</para></listitem>
 421      </varlistentry>
 422    </variablelist>
 423  </refsect1>
 424
 425  <refsect1><title>How APT calls dpkg</title>
 426    <para>Several configuration directives control how APT invokes &dpkg;. These are
 427    in the <literal>DPkg</literal> section.</para>
 428
 429    <variablelist>
 430      <varlistentry><term>options</term>
 431      <listitem><para>This is a list of options to pass to dpkg. The options must be specified
 432      using the list notation and each list item is passed as a single argument
 433      to &dpkg;.</para></listitem>
 434      </varlistentry>
 435
 436      <varlistentry><term>Pre-Invoke</term><term>Post-Invoke</term>
 437      <listitem><para>This is a list of shell commands to run before/after invoking &dpkg;.
 438      Like <literal>options</literal> this must be specified in list notation. The
 439      commands are invoked in order using <filename>/bin/sh</filename>, should any
 440      fail APT will abort.</para></listitem>
 441      </varlistentry>
 442
 443      <varlistentry><term>Pre-Install-Pkgs</term>
 444      <listitem><para>This is a list of shell commands to run before invoking dpkg. Like
 445      <literal>options</literal> this must be specified in list notation. The commands
 446      are invoked in order using <filename>/bin/sh</filename>, should any fail APT
 447      will abort. APT will pass to the commands on standard input the
 448      filenames of all .deb files it is going to install, one per line.</para>
 449
 450      <para>Version 2 of this protocol dumps more information, including the
 451      protocol version, the APT configuration space and the packages, files
 452      and versions being changed. Version 2 is enabled by setting
 453      <literal>DPkg::Tools::options::cmd::Version</literal> to 2. <literal>cmd</literal> is a
 454      command given to <literal>Pre-Install-Pkgs</literal>.</para></listitem>
 455      </varlistentry>
 456
 457      <varlistentry><term>Run-Directory</term>
 458      <listitem><para>APT chdirs to this directory before invoking dpkg, the default is
 459      <filename>/</filename>.</para></listitem>
 460      </varlistentry>
 461
 462      <varlistentry><term>Build-options</term>
 463      <listitem><para>These options are passed to &dpkg-buildpackage; when compiling packages,
 464      the default is to disable signing and produce all binaries.</para></listitem>
 465      </varlistentry>
 466    </variablelist>
 467
 468    <refsect2><title>dpkg trigger usage (and related options)</title>
 469      <para>APT can call dpkg in a way so it can make aggressive use of triggers over
 470      multiply calls of dpkg. Without further options dpkg will use triggers only in between his
 471      own run. Activating these options can therefore decrease the time needed to perform the
 472      install / upgrade. Note that it is intended to activate these options per default in the
 473      future, but as it changes the way APT calling dpkg drastical it needs a lot more testing.
 474      <emphasis>These options are therefore currently experimental and should not be used in
 475      productive environments.</emphasis> Also it breaks the progress reporting so all frontends will
 476      currently stay around half (or more) of the time in the 100% state while it actually configures
 477      all packages.</para>
 478      <para>Note that it is not garanteed that APT will support these options or that these options will
 479      not cause (big) trouble in the future. If you have understand the current risks and problems with
 480      these options, but are brave enough to help testing them create a new configuration file and test a
 481      combination of options. Please report any bugs, problems and improvements you encounter and make sure
 482      to note which options you have used in your reports. Asking dpkg for help could also be useful for
 483      debugging proposes, see e.g. <command>dpkg --audit</command>. A defensive option combination would be
 484 <literallayout>DPkg::NoTriggers "true";
 485 PackageManager::Configure "smart";
 486 DPkg::ConfigurePending "true";
 487 DPkg::TriggersPending "true";</literallayout></para>
 488
 489      <variablelist>
 490        <varlistentry><term>DPkg::NoTriggers</term>
 491        <listitem><para>Add the no triggers flag to all dpkg calls (expect the ConfigurePending call).
 492        See &dpkg; if you are interested in what this actually means. In short: dpkg will not run the
 493        triggers then this flag is present unless it is explicit called to do so in an extra call.
 494        Note that this option exists (undocumented) also in older apt versions with a slightly different
 495        meaning: Previously these option only append --no-triggers to the configure calls to dpkg -
 496        now apt will add these flag also to the unpack and remove calls.</para></listitem>
 497        </varlistentry>
 498        <varlistentry><term>PackageManager::Configure</term>
 499        <listitem><para>Valid values are "<literal>all</literal>", "<literal>smart</literal>" and "<literal>no</literal>".
 500        "<literal>all</literal>" is the default value and causes APT to configure all packages explicit.
 501        The "<literal>smart</literal>" way is it to configure only packages which need to be configured before
 502        another package can be unpacked (Pre-Depends) and let the rest configure by dpkg with a call generated
 503        by the next option. "<literal>no</literal>" on the other hand will not configure anything and totally
 504        relay on dpkg for configuration (which will at the moment fail if a Pre-Depends is encountered).
 505        Setting this option to another than the all value will implicit activate also the next option per
 506        default as otherwise the system could end in an unconfigured status which could be unbootable!
 507        </para></listitem>
 508        </varlistentry>
 509        <varlistentry><term>DPkg::ConfigurePending</term>
 510        <listitem><para>If this option is set apt will call <command>dpkg --configure --pending</command>
 511        to let dpkg handle all required configurations and triggers. This option is activated automatic
 512        per default if the previous option is not set to <literal>all</literal>, but deactivating could be useful
 513        if you want to run APT multiple times in a row - e.g. in an installer. In this sceneries you could
 514        deactivate this option in all but the last run.</para></listitem>
 515        </varlistentry>
 516        <varlistentry><term>DPkg::TriggersPending</term>
 517        <listitem><para>Useful for <literal>smart</literal> configuration as a package which has pending
 518        triggers is not considered as <literal>installed</literal> and dpkg treats them as <literal>unpacked</literal>
 519        currently which is a dealbreaker for Pre-Dependencies (see debbugs #526774). Note that this will
 520        process all triggers, not only the triggers needed to configure this package.</para></listitem>
 521        </varlistentry>
 522        <varlistentry><term>PackageManager::UnpackAll</term>
 523        <listitem><para>As the configuration can be deferred to be done at the end by dpkg it can be
 524        tried to order the unpack series only by critical needs, e.g. by Pre-Depends. Default is true
 525        and therefore the "old" method of ordering in verious steps by everything. While both method
 526        were present in earlier APT versions the <literal>OrderCritical</literal> method was unused, so
 527        this method is very experimental and needs further improvements before becoming really useful.
 528        </para></listitem>
 529        </varlistentry>
 530        <varlistentry><term>OrderList::Score::Immediate</term>
 531        <listitem><para>Essential packages (and there dependencies) should be configured immediately
 532        after unpacking. It will be a good idea to do this quite early in the upgrade process as these
 533        these configure calls require currently also <literal>DPkg::TriggersPending</literal> which
 534        will run quite a few triggers (which maybe not needed). Essentials get per default a high score
 535        but the immediate flag is relativly low (a package which has a Pre-Depends is higher rated).
 536        These option and the others in the same group can be used to change the scoring. The following
 537        example shows the settings with there default values.
 538        <literallayout>OrderList::Score {
 539         Delete 500;
 540         Essential 200;
 541         Immediate 10;
 542         PreDepends 50;
 543 };</literallayout>
 544        </para></listitem>
 545        </varlistentry>
 546      </variablelist>
 547    </refsect2>
 548  </refsect1>
 549
 550  <refsect1>
 551    <title>Periodic and Archives options</title>
 552    <para><literal>APT::Periodic</literal> and <literal>APT::Archives</literal>
 553    groups of options configure behavior of apt periodic updates, which is
 554    done by <literal>/etc/cron.daily/apt</literal> script. See header of
 555    this script for the brief documentation of these options.
 556    </para>
 557  </refsect1>
 558
 559  <refsect1>
 560    <title>Debug options</title>
 561    <para>
 562      Enabling options in the <literal>Debug::</literal> section will
 563      cause debugging information to be sent to the standard error
 564      stream of the program utilizing the <literal>apt</literal>
 565      libraries, or enable special program modes that are primarily
 566      useful for debugging the behavior of <literal>apt</literal>.
 567      Most of these options are not interesting to a normal user, but a
 568      few may be:
 569
 570      <itemizedlist>
 571        <listitem>
 572          <para>
 573            <literal>Debug::pkgProblemResolver</literal> enables output
 574            about the decisions made by
 575            <literal>dist-upgrade, upgrade, install, remove, purge</literal>.
 576          </para>
 577        </listitem>
 578
 579        <listitem>
 580          <para>
 581            <literal>Debug::NoLocking</literal> disables all file
 582            locking.  This can be used to run some operations (for
 583            instance, <literal>apt-get -s install</literal>) as a
 584            non-root user.
 585          </para>
 586        </listitem>
 587
 588        <listitem>
 589          <para>
 590            <literal>Debug::pkgDPkgPM</literal> prints out the actual
 591            command line each time that <literal>apt</literal> invokes
 592            &dpkg;.
 593          </para>
 594        </listitem>
 595
 596        <listitem>
 597          <para>
 598            <literal>Debug::IdentCdrom</literal> disables the inclusion
 599            of statfs data in CDROM IDs.  <!-- TODO: provide a
 600            motivating example, except I haven't a clue why you'd want
 601            to do this. -->
 602          </para>
 603        </listitem>
 604      </itemizedlist>
 605    </para>
 606
 607    <para>
 608      A full list of debugging options to apt follows.
 609    </para>
 610
 611    <variablelist>
 612      <varlistentry>
 613        <term><literal>Debug::Acquire::cdrom</literal></term>
 614
 615        <listitem>
 616          <para>
 617            Print information related to accessing
 618            <literal>cdrom://</literal> sources.
 619          </para>
 620        </listitem>
 621      </varlistentry>
 622
 623      <varlistentry>
 624        <term><literal>Debug::Acquire::ftp</literal></term>
 625
 626        <listitem>
 627          <para>
 628            Print information related to downloading packages using
 629            FTP.
 630          </para>
 631        </listitem>
 632      </varlistentry>
 633
 634      <varlistentry>
 635        <term><literal>Debug::Acquire::http</literal></term>
 636
 637        <listitem>
 638          <para>
 639            Print information related to downloading packages using
 640            HTTP.
 641          </para>
 642        </listitem>
 643      </varlistentry>
 644
 645      <varlistentry>
 646        <term><literal>Debug::Acquire::https</literal></term>
 647
 648        <listitem>
 649          <para>
 650            Print information related to downloading packages using
 651            HTTPS.
 652          </para>
 653        </listitem>
 654      </varlistentry>
 655
 656      <varlistentry>
 657        <term><literal>Debug::Acquire::gpgv</literal></term>
 658
 659        <listitem>
 660          <para>
 661            Print information related to verifying cryptographic
 662            signatures using <literal>gpg</literal>.
 663          </para>
 664        </listitem>
 665      </varlistentry>
 666
 667      <varlistentry>
 668        <term><literal>Debug::aptcdrom</literal></term>
 669
 670        <listitem>
 671          <para>
 672            Output information about the process of accessing
 673            collections of packages stored on CD-ROMs.
 674          </para>
 675        </listitem>
 676      </varlistentry>
 677
 678      <varlistentry>
 679        <term><literal>Debug::BuildDeps</literal></term>
 680        <listitem>
 681          <para>
 682            Describes the process of resolving build-dependencies in
 683            &apt-get;.
 684          </para>
 685        </listitem>
 686      </varlistentry>
 687
 688      <varlistentry>
 689        <term><literal>Debug::Hashes</literal></term>
 690        <listitem>
 691          <para>
 692            Output each cryptographic hash that is generated by the
 693            <literal>apt</literal> libraries.
 694          </para>
 695        </listitem>
 696      </varlistentry>
 697
 698      <varlistentry>
 699        <term><literal>Debug::IdentCDROM</literal></term>
 700        <listitem>
 701          <para>
 702            Do not include information from <literal>statfs</literal>,
 703            namely the number of used and free blocks on the CD-ROM
 704            filesystem, when generating an ID for a CD-ROM.
 705          </para>
 706        </listitem>
 707      </varlistentry>
 708
 709      <varlistentry>
 710        <term><literal>Debug::NoLocking</literal></term>
 711        <listitem>
 712          <para>
 713            Disable all file locking.  For instance, this will allow
 714            two instances of <quote><literal>apt-get
 715            update</literal></quote> to run at the same time.
 716          </para>
 717        </listitem>
 718      </varlistentry>
 719
 720      <varlistentry>
 721        <term><literal>Debug::pkgAcquire</literal></term>
 722
 723        <listitem>
 724          <para>
 725            Log when items are added to or removed from the global
 726            download queue.
 727          </para>
 728        </listitem>
 729      </varlistentry>
 730
 731      <varlistentry>
 732        <term><literal>Debug::pkgAcquire::Auth</literal></term>
 733        <listitem>
 734          <para>
 735            Output status messages and errors related to verifying
 736            checksums and cryptographic signatures of downloaded files.
 737          </para>
 738        </listitem>
 739      </varlistentry>
 740
 741      <varlistentry>
 742        <term><literal>Debug::pkgAcquire::Diffs</literal></term>
 743        <listitem>
 744          <para>
 745            Output information about downloading and applying package
 746            index list diffs, and errors relating to package index list
 747            diffs.
 748          </para>
 749        </listitem>
 750      </varlistentry>
 751
 752      <varlistentry>
 753        <term><literal>Debug::pkgAcquire::RRed</literal></term>
 754
 755        <listitem>
 756          <para>
 757            Output information related to patching apt package lists
 758            when downloading index diffs instead of full indices.
 759          </para>
 760        </listitem>
 761      </varlistentry>
 762
 763      <varlistentry>
 764        <term><literal>Debug::pkgAcquire::Worker</literal></term>
 765
 766        <listitem>
 767          <para>
 768            Log all interactions with the sub-processes that actually
 769            perform downloads.
 770          </para>
 771        </listitem>
 772      </varlistentry>
 773
 774      <varlistentry>
 775        <term><literal>Debug::pkgAutoRemove</literal></term>
 776
 777        <listitem>
 778          <para>
 779            Log events related to the automatically-installed status of
 780            packages and to the removal of unused packages.
 781          </para>
 782        </listitem>
 783      </varlistentry>
 784
 785      <varlistentry>
 786        <term><literal>Debug::pkgDepCache::AutoInstall</literal></term>
 787        <listitem>
 788          <para>
 789            Generate debug messages describing which packages are being
 790            automatically installed to resolve dependencies.  This
 791            corresponds to the initial auto-install pass performed in,
 792            e.g., <literal>apt-get install</literal>, and not to the
 793            full <literal>apt</literal> dependency resolver; see
 794            <literal>Debug::pkgProblemResolver</literal> for that.
 795          </para>
 796        </listitem>
 797      </varlistentry>
 798
 799      <varlistentry>
 800        <term><literal>Debug::pkgDepCache::Marker</literal></term>
 801        <listitem>
 802         <para>
 803            Generate debug messages describing which package is marked
 804           as keep/install/remove while the ProblemResolver does his work.
 805           Each addition or deletion may trigger additional actions;
 806           they are shown indented two additional space under the original entry.
 807           The format for each line is <literal>MarkKeep</literal>,
 808           <literal>MarkDelete</literal> or <literal>MarkInstall</literal> followed by
 809           <literal>package-name &lt;a.b.c -&gt; d.e.f | x.y.z&gt; (section)</literal>
 810           where <literal>a.b.c</literal> is the current version of the package,
 811           <literal>d.e.f</literal> is the version considered for installation and
 812           <literal>x.y.z</literal> is a newer version, but not considered for installation
 813           (because of a low pin score). The later two can be omitted if there is none or if
 814           it is the same version as the installed.
 815           <literal>section</literal> is the name of the section the package appears in.
 816         </para>
 817        </listitem>
 818      </varlistentry>
 819
 820      <!-- Question: why doesn't this do anything?  The code says it should. -->
 821      <varlistentry>
 822        <term><literal>Debug::pkgInitConfig</literal></term>
 823        <listitem>
 824          <para>
 825            Dump the default configuration to standard error on
 826            startup.
 827          </para>
 828        </listitem>
 829      </varlistentry>
 830
 831      <varlistentry>
 832        <term><literal>Debug::pkgDPkgPM</literal></term>
 833        <listitem>
 834          <para>
 835            When invoking &dpkg;, output the precise command line with
 836            which it is being invoked, with arguments separated by a
 837            single space character.
 838          </para>
 839        </listitem>
 840      </varlistentry>
 841
 842      <varlistentry>
 843        <term><literal>Debug::pkgDPkgProgressReporting</literal></term>
 844        <listitem>
 845          <para>
 846            Output all the data received from &dpkg; on the status file
 847            descriptor and any errors encountered while parsing it.
 848          </para>
 849        </listitem>
 850      </varlistentry>
 851
 852      <varlistentry>
 853        <term><literal>Debug::pkgOrderList</literal></term>
 854
 855        <listitem>
 856          <para>
 857            Generate a trace of the algorithm that decides the order in
 858            which <literal>apt</literal> should pass packages to
 859            &dpkg;.
 860          </para>
 861        </listitem>
 862      </varlistentry>
 863
 864      <varlistentry>
 865        <term><literal>Debug::pkgPackageManager</literal></term>
 866
 867        <listitem>
 868          <para>
 869            Output status messages tracing the steps performed when
 870            invoking &dpkg;.
 871          </para>
 872        </listitem>
 873      </varlistentry>
 874
 875      <varlistentry>
 876        <term><literal>Debug::pkgPolicy</literal></term>
 877
 878        <listitem>
 879          <para>
 880            Output the priority of each package list on startup.
 881          </para>
 882        </listitem>
 883      </varlistentry>
 884
 885      <varlistentry>
 886        <term><literal>Debug::pkgProblemResolver</literal></term>
 887
 888        <listitem>
 889          <para>
 890            Trace the execution of the dependency resolver (this
 891            applies only to what happens when a complex dependency
 892            problem is encountered).
 893          </para>
 894        </listitem>
 895      </varlistentry>
 896
 897      <varlistentry>
 898        <term><literal>Debug::pkgProblemResolver::ShowScores</literal></term>
 899        <listitem>
 900         <para>
 901           Display a list of all installed packages with their calculated score
 902           used by the pkgProblemResolver. The description of the package
 903           is the same as described in <literal>Debug::pkgDepCache::Marker</literal>
 904         </para>
 905        </listitem>
 906      </varlistentry>
 907
 908      <varlistentry>
 909        <term><literal>Debug::sourceList</literal></term>
 910
 911        <listitem>
 912          <para>
 913            Print information about the vendors read from
 914            <filename>/etc/apt/vendors.list</filename>.
 915          </para>
 916        </listitem>
 917      </varlistentry>
 918
 919 <!-- 2009/07/11 Currently used nowhere. The corresponding code
 920 is commented.
 921      <varlistentry>
 922        <term><literal>Debug::Vendor</literal></term>
 923
 924        <listitem>
 925          <para>
 926            Print information about each vendor.
 927          </para>
 928        </listitem>
 929      </varlistentry>
 930 -->
 931    </variablelist>
 932  </refsect1>
 933
 934  <refsect1><title>Examples</title>
 935    <para>&configureindex; is a
 936    configuration file showing example values for all possible
 937    options.</para>
 938  </refsect1>
 939
 940  <refsect1><title>Files</title>
 941    <variablelist>
 942       &file-aptconf;
 943    </variablelist>
 944  </refsect1>
 945
 946  <refsect1><title>See Also</title>
 947    <para>&apt-cache;, &apt-config;<!-- ? reading apt.conf -->, &apt-preferences;.</para>
 948  </refsect1>
 949
 950  &manbugs;
 951
 952 </refentry>
 953