doc/apt.conf.5.xml

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   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>10 December 2008</date>
  25  </refentryinfo>
  26
  27  <refmeta>
  28    <refentrytitle>apt.conf</refentrytitle>
  29    <manvolnum>5</manvolnum>
  30  </refmeta>
  31
  32  <!-- Man page title -->
  33  <refnamediv>
  34     <refname>apt.conf</refname>
  35     <refpurpose>Configuration file for APT</refpurpose>
  36  </refnamediv>
  37
  38  <refsect1><title>Description</title>
  39    <para><filename>apt.conf</filename> is the main configuration file for the APT suite of
  40    tools, all tools make use of the configuration file and a common command line
  41    parser to provide a uniform environment. When an APT tool starts up it will
  42    read the configuration specified by the <envar>APT_CONFIG</envar> environment
  43    variable (if any) and then read the files in <literal>Dir::Etc::Parts</literal>
  44    then read the main configuration file specified by
  45    <literal>Dir::Etc::main</literal> then finally apply the
  46    command line options to override the configuration directives, possibly
  47    loading even more config files.</para>
  48
  49    <para>The configuration file is organized in a tree with options organized into
  50    functional groups. option specification is given with a double colon
  51    notation, for instance <literal>APT::Get::Assume-Yes</literal> is an option within
  52    the APT tool group, for the Get tool. options do not inherit from their
  53    parent groups.</para>
  54
  55    <para>Syntactically the configuration language is modeled after what the ISC tools
  56    such as bind and dhcp use. Lines starting with
  57    <literal>//</literal> are treated as comments (ignored), as well as all text
  58    between <literal>/*</literal> and <literal>*/</literal>, just like C/C++ comments.
  59    Each line is of the form
  60    <literal>APT::Get::Assume-Yes "true";</literal> The trailing
  61    semicolon is required and the quotes are optional. A new scope can be
  62    opened with curly braces, like:</para>
  63
  64 <informalexample><programlisting>
  65 APT {
  66   Get {
  67     Assume-Yes "true";
  68     Fix-Broken "true";
  69   };
  70 };
  71 </programlisting></informalexample>
  72
  73    <para>with newlines placed to make it more readable. Lists can be created by
  74    opening a scope and including a single string enclosed in quotes followed by a
  75    semicolon. Multiple entries can be included, each separated by a semicolon.</para>
  76
  77 <informalexample><programlisting>
  78 DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt";};
  79 </programlisting></informalexample>
  80
  81    <para>In general the sample configuration file in
  82    <filename>&docdir;examples/apt.conf</filename> &configureindex;
  83    is a good guide for how it should look.</para>
  84
  85    <para>The names of the configuration items are not case-sensitive. So in the previous example
  86    you could use <literal>dpkg::pre-install-pkgs</literal>.</para>
  87
  88    <para>Two specials are allowed, <literal>#include</literal> and <literal>#clear</literal>
  89    <literal>#include</literal> will include the given file, unless the filename
  90    ends in a slash, then the whole directory is included.
  91    <literal>#clear</literal> is used to erase a part of the configuration tree. The
  92    specified element and all its descendents are erased.</para>
  93
  94    <para>All of the APT tools take a -o option which allows an arbitrary configuration
  95    directive to be specified on the command line. The syntax is a full option
  96    name (<literal>APT::Get::Assume-Yes</literal> for instance) followed by an equals
  97    sign then the new value of the option. Lists can be appended too by adding
  98    a trailing :: to the list name.</para>
  99  </refsect1>
 100
 101  <refsect1><title>The APT Group</title>
 102    <para>This group of options controls general APT behavior as well as holding the
 103    options for all of the tools.</para>
 104
 105    <variablelist>
 106      <varlistentry><term>Architecture</term>
 107      <listitem><para>System Architecture; sets the architecture to use when fetching files and
 108      parsing package lists. The internal default is the architecture apt was
 109      compiled for.</para></listitem>
 110      </varlistentry>
 111
 112      <varlistentry><term>Default-Release</term>
 113          <listitem><para>Default release to install packages from if more than one
 114          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>
 115      </varlistentry>
 116
 117      <varlistentry><term>Ignore-Hold</term>
 118      <listitem><para>Ignore Held packages; This global option causes the problem resolver to
 119      ignore held packages in its decision making.</para></listitem>
 120      </varlistentry>
 121
 122      <varlistentry><term>Clean-Installed</term>
 123      <listitem><para>Defaults to on. When turned on the autoclean feature will remove any packages
 124      which can no longer be downloaded from the cache. If turned off then
 125      packages that are locally installed are also excluded from cleaning - but
 126      note that APT provides no direct means to reinstall them.</para></listitem>
 127      </varlistentry>
 128
 129      <varlistentry><term>Immediate-Configure</term>
 130      <listitem><para>Disable Immediate Configuration; This dangerous option disables some
 131      of APT's ordering code to cause it to make fewer dpkg calls. Doing
 132      so may be necessary on some extremely slow single user systems but
 133      is very dangerous and may cause package install scripts to fail or worse.
 134      Use at your own risk.</para></listitem>
 135      </varlistentry>
 136
 137      <varlistentry><term>Force-LoopBreak</term>
 138      <listitem><para>Never Enable this option unless you -really- know what you are doing. It
 139      permits APT to temporarily remove an essential package to break a
 140      Conflicts/Conflicts or Conflicts/Pre-Depend loop between two essential
 141      packages. SUCH A LOOP SHOULD NEVER EXIST AND IS A GRAVE BUG. This option
 142      will work if the essential packages are not tar, gzip, libc, dpkg, bash or
 143      anything that those packages depend on.</para></listitem>
 144      </varlistentry>
 145
 146      <varlistentry><term>Cache-Limit</term>
 147      <listitem><para>APT uses a fixed size memory mapped cache file to store the 'available'
 148      information. This sets the size of that cache (in bytes).</para></listitem>
 149      </varlistentry>
 150
 151      <varlistentry><term>Build-Essential</term>
 152      <listitem><para>Defines which package(s) are considered essential build dependencies.</para></listitem>
 153      </varlistentry>
 154
 155      <varlistentry><term>Get</term>
 156      <listitem><para>The Get subsection controls the &apt-get; tool, please see its
 157      documentation for more information about the options here.</para></listitem>
 158      </varlistentry>
 159
 160      <varlistentry><term>Cache</term>
 161      <listitem><para>The Cache subsection controls the &apt-cache; tool, please see its
 162      documentation for more information about the options here.</para></listitem>
 163      </varlistentry>
 164
 165      <varlistentry><term>CDROM</term>
 166      <listitem><para>The CDROM subsection controls the &apt-cdrom; tool, please see its
 167      documentation for more information about the options here.</para></listitem>
 168      </varlistentry>
 169    </variablelist>
 170  </refsect1>
 171
 172  <refsect1><title>The Acquire Group</title>
 173    <para>The <literal>Acquire</literal> group of options controls the download of packages
 174    and the URI handlers.
 175
 176    <variablelist>
 177      <varlistentry><term>PDiffs</term>
 178          <listitem><para>Try to download deltas called <literal>PDiffs</literal> for
 179          Packages or Sources files instead of downloading whole ones. True
 180          by default.</para></listitem>
 181      </varlistentry>
 182
 183      <varlistentry><term>Queue-Mode</term>
 184      <listitem><para>Queuing mode; <literal>Queue-Mode</literal> can be one of <literal>host</literal> or
 185      <literal>access</literal> which determines how  APT parallelizes outgoing
 186      connections. <literal>host</literal> means that one connection per target host
 187      will be opened, <literal>access</literal> means that one connection per URI type
 188      will be opened.</para></listitem>
 189      </varlistentry>
 190
 191      <varlistentry><term>Retries</term>
 192      <listitem><para>Number of retries to perform. If this is non-zero APT will retry failed
 193      files the given number of times.</para></listitem>
 194      </varlistentry>
 195
 196      <varlistentry><term>Source-Symlinks</term>
 197      <listitem><para>Use symlinks for source archives. If set to true then source archives will
 198      be symlinked when possible instead of copying. True is the default.</para></listitem>
 199      </varlistentry>
 200
 201      <varlistentry><term>http</term>
 202      <listitem><para>HTTP URIs; http::Proxy is the default http proxy to use. It is in the
 203      standard form of <literal>http://[[user][:pass]@]host[:port]/</literal>. Per
 204      host proxies can also be specified by using the form
 205      <literal>http::Proxy::&lt;host&gt;</literal> with the special keyword <literal>DIRECT</literal>
 206          meaning to use no proxies. If no one of the above settings is specified,
 207          <envar>http_proxy</envar> environment variable
 208          will be used.</para>
 209
 210      <para>Three settings are provided for cache control with HTTP/1.1 compliant
 211      proxy caches. <literal>No-Cache</literal> tells the proxy to not use its cached
 212      response under any circumstances, <literal>Max-Age</literal> is sent only for
 213      index files and tells the cache to refresh its object if it is older than
 214      the given number of seconds. Debian updates its index files daily so the
 215      default is 1 day. <literal>No-Store</literal> specifies that the cache should never
 216      store this request, it is only set for archive files. This may be useful
 217      to prevent polluting a proxy cache with very large .deb files. Note:
 218      Squid 2.0.2 does not support any of these options.</para>
 219
 220      <para>The option <literal>timeout</literal> sets the timeout timer used by the method,
 221      this applies to all things including connection timeout and data timeout.</para>
 222
 223      <para>One setting is provided to control the pipeline depth in cases where the
 224      remote server is not RFC conforming or buggy (such as Squid 2.0.2)
 225      <literal>Acquire::http::Pipeline-Depth</literal> can be a value from 0 to 5
 226      indicating how many outstanding requests APT should send. A value of
 227      zero MUST be specified if the remote host does not properly linger
 228      on TCP connections - otherwise data corruption will occur. Hosts which
 229      require this are in violation of RFC 2068.</para></listitem>
 230      </varlistentry>
 231
 232      <varlistentry><term>https</term>
 233          <listitem><para>HTTPS URIs. Cache-control and proxy options are the same as for
 234          <literal>http</literal> method.
 235          <literal>Pipeline-Depth</literal> option is not supported yet.</para>
 236
 237          <para><literal>CaInfo</literal> suboption specifies place of file that
 238          holds info about trusted certificates.
 239          <literal>&lt;host&gt;::CaInfo</literal> is corresponding per-host option.
 240          <literal>Verify-Peer</literal> boolean suboption determines whether verify
 241          server's host certificate against trusted certificates or not.
 242          <literal>&lt;host&gt;::Verify-Peer</literal> is corresponding per-host option.
 243          <literal>Verify-Host</literal> boolean suboption determines whether verify
 244          server's hostname or not.
 245          <literal>&lt;host&gt;::Verify-Host</literal> is corresponding per-host option.
 246          <literal>SslCert</literal> determines what certificate to use for client
 247          authentication. <literal>&lt;host&gt;::SslCert</literal> is corresponding per-host option.
 248          <literal>SslKey</literal> determines what private key to use for client
 249          authentication. <literal>&lt;host&gt;::SslKey</literal> is corresponding per-host option.
 250          <literal>SslForceVersion</literal> overrides default SSL version to use.
 251          Can contain 'TLSv1' or 'SSLv3' string.
 252          <literal>&lt;host&gt;::SslForceVersion</literal> is corresponding per-host option.
 253          </para></listitem></varlistentry>
 254
 255      <varlistentry><term>ftp</term>
 256      <listitem><para>FTP URIs; ftp::Proxy is the default ftp proxy to use. It is in the
 257      standard form of <literal>ftp://[[user][:pass]@]host[:port]/</literal>. Per
 258      host proxies can also be specified by using the form
 259      <literal>ftp::Proxy::&lt;host&gt;</literal> with the special keyword <literal>DIRECT</literal>
 260          meaning to use no proxies. If no one of the above settings is specified,
 261          <envar>ftp_proxy</envar> environment variable
 262          will be used. To use a ftp
 263      proxy you will have to set the <literal>ftp::ProxyLogin</literal> script in the
 264      configuration file. This entry specifies the commands to send to tell
 265      the proxy server what to connect to. Please see
 266      &configureindex; for an example of
 267      how to do this. The substitution variables available are
 268      <literal>$(PROXY_USER)</literal> <literal>$(PROXY_PASS)</literal> <literal>$(SITE_USER)</literal>
 269      <literal>$(SITE_PASS)</literal> <literal>$(SITE)</literal> and <literal>$(SITE_PORT)</literal>
 270      Each is taken from it's respective URI component.</para>
 271
 272      <para>The option <literal>timeout</literal> sets the timeout timer used by the method,
 273      this applies to all things including connection timeout and data timeout.</para>
 274
 275      <para>Several settings are provided to control passive mode. Generally it is
 276      safe to leave passive mode on, it works in nearly every environment.
 277      However some situations require that passive mode be disabled and port
 278      mode ftp used instead. This can be done globally, for connections that
 279      go through a proxy or for a specific host (See the sample config file
 280      for examples).</para>
 281
 282      <para>It is possible to proxy FTP over HTTP by setting the <envar>ftp_proxy</envar>
 283      environment variable to a http url - see the discussion of the http method
 284      above for syntax. You cannot set this in the configuration file and it is
 285      not recommended to use FTP over HTTP due to its low efficiency.</para>
 286
 287      <para>The setting <literal>ForceExtended</literal> controls the use of RFC2428
 288      <literal>EPSV</literal> and <literal>EPRT</literal> commands. The default is false, which means
 289      these commands are only used if the control connection is IPv6. Setting this
 290      to true forces their use even on IPv4 connections. Note that most FTP servers
 291      do not support RFC2428.</para></listitem>
 292      </varlistentry>
 293
 294      <varlistentry><term>cdrom</term>
 295      <listitem><para>CDROM URIs; the only setting for CDROM URIs is the mount point,
 296      <literal>cdrom::Mount</literal> which must be the mount point for the CDROM drive
 297      as specified in <filename>/etc/fstab</filename>. It is possible to provide
 298      alternate mount and unmount commands if your mount point cannot be listed
 299      in the fstab (such as an SMB mount and old mount packages). The syntax
 300      is to put <literallayout>"/cdrom/"::Mount "foo";</literallayout> within
 301      the cdrom block. It is important to have the trailing slash. Unmount
 302      commands can be specified using UMount.</para></listitem>
 303      </varlistentry>
 304
 305      <varlistentry><term>gpgv</term>
 306      <listitem><para>GPGV URIs; the only option for GPGV URIs is the option to pass additional parameters to gpgv.
 307      <literal>gpgv::Options</literal> Additional options passed to gpgv.
 308      </para></listitem>
 309      </varlistentry>
 310
 311    </variablelist>
 312   </para>
 313  </refsect1>
 314
 315  <refsect1><title>Directories</title>
 316
 317    <para>The <literal>Dir::State</literal> section has directories that pertain to local
 318    state information. <literal>lists</literal> is the directory to place downloaded
 319    package lists in and <literal>status</literal> is the name of the dpkg status file.
 320    <literal>preferences</literal> is the name of the APT preferences file.
 321    <literal>Dir::State</literal> contains the default directory to prefix on all sub
 322    items if they do not start with <filename>/</filename> or <filename>./</filename>.</para>
 323
 324    <para><literal>Dir::Cache</literal> contains locations pertaining to local cache
 325    information, such as the two package caches <literal>srcpkgcache</literal> and
 326    <literal>pkgcache</literal> as well as the location to place downloaded archives,
 327    <literal>Dir::Cache::archives</literal>. Generation of caches can be turned off
 328    by setting their names to be blank. This will slow down startup but
 329    save disk space. It is probably preferred to turn off the pkgcache rather
 330    than the srcpkgcache. Like <literal>Dir::State</literal> the default
 331    directory is contained in <literal>Dir::Cache</literal></para>
 332
 333    <para><literal>Dir::Etc</literal> contains the location of configuration files,
 334    <literal>sourcelist</literal> gives the location of the sourcelist and
 335    <literal>main</literal> is the default configuration file (setting has no effect,
 336    unless it is done from the config file specified by
 337    <envar>APT_CONFIG</envar>).</para>
 338
 339    <para>The <literal>Dir::Parts</literal> setting reads in all the config fragments in
 340    lexical order from the directory specified. After this is done then the
 341    main config file is loaded.</para>
 342
 343    <para>Binary programs are pointed to by <literal>Dir::Bin</literal>. <literal>Dir::Bin::Methods</literal>
 344    specifies the location of the method handlers and <literal>gzip</literal>,
 345    <literal>dpkg</literal>, <literal>apt-get</literal> <literal>dpkg-source</literal>
 346    <literal>dpkg-buildpackage</literal> and <literal>apt-cache</literal> specify the location
 347    of the respective programs.</para>
 348
 349    <para>
 350      The configuration item <literal>RootDir</literal> has a special
 351      meaning.  If set, all paths in <literal>Dir::</literal> will be
 352      relative to <literal>RootDir</literal>, <emphasis>even paths that
 353      are specified absolutely</emphasis>.  So, for instance, if
 354      <literal>RootDir</literal> is set to
 355      <filename>/tmp/staging</filename> and
 356      <literal>Dir::State::status</literal> is set to
 357      <filename>/var/lib/dpkg/status</filename>, then the status file
 358      will be looked up in
 359      <filename>/tmp/staging/var/lib/dpkg/status</filename>.
 360    </para>
 361  </refsect1>
 362
 363  <refsect1><title>APT in DSelect</title>
 364    <para>
 365    When APT is used as a &dselect; method several configuration directives
 366    control the default behaviour. These are in the <literal>DSelect</literal> section.</para>
 367
 368    <variablelist>
 369      <varlistentry><term>Clean</term>
 370      <listitem><para>Cache Clean mode; this value may be one of always, prompt, auto,
 371      pre-auto and never.  always and prompt will remove all packages from
 372      the cache after upgrading, prompt (the default) does so conditionally.
 373      auto removes only those packages which are no longer downloadable
 374      (replaced with a new version for instance).  pre-auto performs this
 375      action before downloading new packages.</para></listitem>
 376      </varlistentry>
 377
 378      <varlistentry><term>options</term>
 379      <listitem><para>The contents of this variable is passed to &apt-get; as command line
 380      options when it is run for the install phase.</para></listitem>
 381      </varlistentry>
 382
 383      <varlistentry><term>Updateoptions</term>
 384      <listitem><para>The contents of this variable is passed to &apt-get; as command line
 385      options when it is run for the update phase.</para></listitem>
 386      </varlistentry>
 387
 388      <varlistentry><term>PromptAfterUpdate</term>
 389      <listitem><para>If true the [U]pdate operation in &dselect; will always prompt to continue.
 390      The default is to prompt only on error.</para></listitem>
 391      </varlistentry>
 392    </variablelist>
 393  </refsect1>
 394
 395  <refsect1><title>How APT calls dpkg</title>
 396    <para>Several configuration directives control how APT invokes &dpkg;. These are
 397    in the <literal>DPkg</literal> section.</para>
 398
 399    <variablelist>
 400      <varlistentry><term>options</term>
 401      <listitem><para>This is a list of options to pass to dpkg. The options must be specified
 402      using the list notation and each list item is passed as a single argument
 403      to &dpkg;.</para></listitem>
 404      </varlistentry>
 405
 406      <varlistentry><term>Pre-Invoke</term><term>Post-Invoke</term>
 407      <listitem><para>This is a list of shell commands to run before/after invoking &dpkg;.
 408      Like <literal>options</literal> this must be specified in list notation. The
 409      commands are invoked in order using <filename>/bin/sh</filename>, should any
 410      fail APT will abort.</para></listitem>
 411      </varlistentry>
 412
 413      <varlistentry><term>Pre-Install-Pkgs</term>
 414      <listitem><para>This is a list of shell commands to run before invoking dpkg. Like
 415      <literal>options</literal> this must be specified in list notation. The commands
 416      are invoked in order using <filename>/bin/sh</filename>, should any fail APT
 417      will abort. APT will pass to the commands on standard input the
 418      filenames of all .deb files it is going to install, one per line.</para>
 419
 420      <para>Version 2 of this protocol dumps more information, including the
 421      protocol version, the APT configuration space and the packages, files
 422      and versions being changed. Version 2 is enabled by setting
 423      <literal>DPkg::Tools::options::cmd::Version</literal> to 2. <literal>cmd</literal> is a
 424      command given to <literal>Pre-Install-Pkgs</literal>.</para></listitem>
 425      </varlistentry>
 426
 427      <varlistentry><term>Run-Directory</term>
 428      <listitem><para>APT chdirs to this directory before invoking dpkg, the default is
 429      <filename>/</filename>.</para></listitem>
 430      </varlistentry>
 431
 432      <varlistentry><term>Build-options</term>
 433      <listitem><para>These options are passed to &dpkg-buildpackage; when compiling packages,
 434      the default is to disable signing and produce all binaries.</para></listitem>
 435      </varlistentry>
 436    </variablelist>
 437  </refsect1>
 438
 439  <refsect1>
 440    <title>Periodic and Archives options</title>
 441    <para><literal>APT::Periodic</literal> and <literal>APT::Archives</literal>
 442    groups of options configure behavior of apt periodic updates, which is
 443    done by <literal>/etc/cron.daily/apt</literal> script. See header of
 444    this script for the brief documentation of these options.
 445    </para>
 446  </refsect1>
 447
 448  <refsect1>
 449    <title>Debug options</title>
 450    <para>
 451      Enabling options in the <literal>Debug::</literal> section will
 452      cause debugging information to be sent to the standard error
 453      stream of the program utilizing the <literal>apt</literal>
 454      libraries, or enable special program modes that are primarily
 455      useful for debugging the behavior of <literal>apt</literal>.
 456      Most of these options are not interesting to a normal user, but a
 457      few may be:
 458
 459      <itemizedlist>
 460        <listitem>
 461          <para>
 462            <literal>Debug::pkgProblemResolver</literal> enables output
 463            about the decisions made by
 464            <literal>dist-upgrade, upgrade, install, remove, purge</literal>.
 465          </para>
 466        </listitem>
 467
 468        <listitem>
 469          <para>
 470            <literal>Debug::NoLocking</literal> disables all file
 471            locking.  This can be used to run some operations (for
 472            instance, <literal>apt-get -s install</literal>) as a
 473            non-root user.
 474          </para>
 475        </listitem>
 476
 477        <listitem>
 478          <para>
 479            <literal>Debug::pkgDPkgPM</literal> prints out the actual
 480            command line each time that <literal>apt</literal> invokes
 481            &dpkg;.
 482          </para>
 483        </listitem>
 484
 485        <listitem>
 486          <para>
 487            <literal>Debug::IdentCdrom</literal> disables the inclusion
 488            of statfs data in CDROM IDs.  <!-- TODO: provide a
 489            motivating example, except I haven't a clue why you'd want
 490            to do this. -->
 491          </para>
 492        </listitem>
 493      </itemizedlist>
 494    </para>
 495
 496    <para>
 497      A full list of debugging options to apt follows.
 498    </para>
 499
 500    <variablelist>
 501      <varlistentry>
 502        <term><literal>Debug::Acquire::cdrom</literal></term>
 503
 504        <listitem>
 505          <para>
 506            Print information related to accessing
 507            <literal>cdrom://</literal> sources.
 508          </para>
 509        </listitem>
 510      </varlistentry>
 511
 512      <varlistentry>
 513        <term><literal>Debug::Acquire::ftp</literal></term>
 514
 515        <listitem>
 516          <para>
 517            Print information related to downloading packages using
 518            FTP.
 519          </para>
 520        </listitem>
 521      </varlistentry>
 522
 523      <varlistentry>
 524        <term><literal>Debug::Acquire::http</literal></term>
 525
 526        <listitem>
 527          <para>
 528            Print information related to downloading packages using
 529            HTTP.
 530          </para>
 531        </listitem>
 532      </varlistentry>
 533
 534      <varlistentry>
 535        <term><literal>Debug::Acquire::https</literal></term>
 536
 537        <listitem>
 538          <para>
 539            Print information related to downloading packages using
 540            HTTPS.
 541          </para>
 542        </listitem>
 543      </varlistentry>
 544
 545      <varlistentry>
 546        <term><literal>Debug::Acquire::gpgv</literal></term>
 547
 548        <listitem>
 549          <para>
 550            Print information related to verifying cryptographic
 551            signatures using <literal>gpg</literal>.
 552          </para>
 553        </listitem>
 554      </varlistentry>
 555
 556      <varlistentry>
 557        <term><literal>Debug::aptcdrom</literal></term>
 558
 559        <listitem>
 560          <para>
 561            Output information about the process of accessing
 562            collections of packages stored on CD-ROMs.
 563          </para>
 564        </listitem>
 565      </varlistentry>
 566
 567      <varlistentry>
 568        <term><literal>Debug::BuildDeps</literal></term>
 569        <listitem>
 570          <para>
 571            Describes the process of resolving build-dependencies in
 572            &apt-get;.
 573          </para>
 574        </listitem>
 575      </varlistentry>
 576
 577      <varlistentry>
 578        <term><literal>Debug::Hashes</literal></term>
 579        <listitem>
 580          <para>
 581            Output each cryptographic hash that is generated by the
 582            <literal>apt</literal> libraries.
 583          </para>
 584        </listitem>
 585      </varlistentry>
 586
 587      <varlistentry>
 588        <term><literal>Debug::IdentCDROM</literal></term>
 589        <listitem>
 590          <para>
 591            Do not include information from <literal>statfs</literal>,
 592            namely the number of used and free blocks on the CD-ROM
 593            filesystem, when generating an ID for a CD-ROM.
 594          </para>
 595        </listitem>
 596      </varlistentry>
 597
 598      <varlistentry>
 599        <term><literal>Debug::NoLocking</literal></term>
 600        <listitem>
 601          <para>
 602            Disable all file locking.  For instance, this will allow
 603            two instances of <quote><literal>apt-get
 604            update</literal></quote> to run at the same time.
 605          </para>
 606        </listitem>
 607      </varlistentry>
 608
 609      <varlistentry>
 610        <term><literal>Debug::pkgAcquire</literal></term>
 611
 612        <listitem>
 613          <para>
 614            Log when items are added to or removed from the global
 615            download queue.
 616          </para>
 617        </listitem>
 618      </varlistentry>
 619
 620      <varlistentry>
 621        <term><literal>Debug::pkgAcquire::Auth</literal></term>
 622        <listitem>
 623          <para>
 624            Output status messages and errors related to verifying
 625            checksums and cryptographic signatures of downloaded files.
 626          </para>
 627        </listitem>
 628      </varlistentry>
 629
 630      <varlistentry>
 631        <term><literal>Debug::pkgAcquire::Diffs</literal></term>
 632        <listitem>
 633          <para>
 634            Output information about downloading and applying package
 635            index list diffs, and errors relating to package index list
 636            diffs.
 637          </para>
 638        </listitem>
 639      </varlistentry>
 640
 641      <varlistentry>
 642        <term><literal>Debug::pkgAcquire::RRed</literal></term>
 643
 644        <listitem>
 645          <para>
 646            Output information related to patching apt package lists
 647            when downloading index diffs instead of full indices.
 648          </para>
 649        </listitem>
 650      </varlistentry>
 651
 652      <varlistentry>
 653        <term><literal>Debug::pkgAcquire::Worker</literal></term>
 654
 655        <listitem>
 656          <para>
 657            Log all interactions with the sub-processes that actually
 658            perform downloads.
 659          </para>
 660        </listitem>
 661      </varlistentry>
 662
 663      <varlistentry>
 664        <term><literal>Debug::pkgAutoRemove</literal></term>
 665
 666        <listitem>
 667          <para>
 668            Log events related to the automatically-installed status of
 669            packages and to the removal of unused packages.
 670          </para>
 671        </listitem>
 672      </varlistentry>
 673
 674      <varlistentry>
 675        <term><literal>Debug::pkgDepCache::AutoInstall</literal></term>
 676        <listitem>
 677          <para>
 678            Generate debug messages describing which packages are being
 679            automatically installed to resolve dependencies.  This
 680            corresponds to the initial auto-install pass performed in,
 681            e.g., <literal>apt-get install</literal>, and not to the
 682            full <literal>apt</literal> dependency resolver; see
 683            <literal>Debug::pkgProblemResolver</literal> for that.
 684          </para>
 685        </listitem>
 686      </varlistentry>
 687
 688      <varlistentry>
 689        <term><literal>Debug::pkgDepCache::Marker</literal></term>
 690        <listitem>
 691         <para>
 692            Generate debug messages describing which package is marked
 693           as keep/install/remove while the ProblemResolver does his work.
 694           Each addition or deletion may trigger additional actions;
 695           they are shown indented two additional space under the original entry.
 696           The format for each line is <literal>MarkKeep</literal>,
 697           <literal>MarkDelete</literal> or <literal>MarkInstall</literal> followed by
 698           <literal>package-name &lt;a.b.c -&gt; d.e.f | x.y.z&gt; (section)</literal>
 699           where <literal>a.b.c</literal> is the current version of the package,
 700           <literal>d.e.f</literal> is the version considered for installation and
 701           <literal>x.y.z</literal> is a newer version, but not considered for installation
 702           (because of a low pin score). The later two can be omitted if there is none or if
 703           it is the same version as the installed.
 704           <literal>section</literal> is the name of the section the package appears in.
 705         </para>
 706        </listitem>
 707      </varlistentry>
 708
 709      <!-- Question: why doesn't this do anything?  The code says it should. -->
 710      <varlistentry>
 711        <term><literal>Debug::pkgInitConfig</literal></term>
 712        <listitem>
 713          <para>
 714            Dump the default configuration to standard error on
 715            startup.
 716          </para>
 717        </listitem>
 718      </varlistentry>
 719
 720      <varlistentry>
 721        <term><literal>Debug::pkgDPkgPM</literal></term>
 722        <listitem>
 723          <para>
 724            When invoking &dpkg;, output the precise command line with
 725            which it is being invoked, with arguments separated by a
 726            single space character.
 727          </para>
 728        </listitem>
 729      </varlistentry>
 730
 731      <varlistentry>
 732        <term><literal>Debug::pkgDPkgProgressReporting</literal></term>
 733        <listitem>
 734          <para>
 735            Output all the data received from &dpkg; on the status file
 736            descriptor and any errors encountered while parsing it.
 737          </para>
 738        </listitem>
 739      </varlistentry>
 740
 741      <varlistentry>
 742        <term><literal>Debug::pkgOrderList</literal></term>
 743
 744        <listitem>
 745          <para>
 746            Generate a trace of the algorithm that decides the order in
 747            which <literal>apt</literal> should pass packages to
 748            &dpkg;.
 749          </para>
 750        </listitem>
 751      </varlistentry>
 752
 753      <varlistentry>
 754        <term><literal>Debug::pkgPackageManager</literal></term>
 755
 756        <listitem>
 757          <para>
 758            Output status messages tracing the steps performed when
 759            invoking &dpkg;.
 760          </para>
 761        </listitem>
 762      </varlistentry>
 763
 764      <varlistentry>
 765        <term><literal>Debug::pkgPolicy</literal></term>
 766
 767        <listitem>
 768          <para>
 769            Output the priority of each package list on startup.
 770          </para>
 771        </listitem>
 772      </varlistentry>
 773
 774      <varlistentry>
 775        <term><literal>Debug::pkgProblemResolver</literal></term>
 776
 777        <listitem>
 778          <para>
 779            Trace the execution of the dependency resolver (this
 780            applies only to what happens when a complex dependency
 781            problem is encountered).
 782          </para>
 783        </listitem>
 784      </varlistentry>
 785
 786      <varlistentry>
 787        <term><literal>Debug::pkgProblemResolver::ShowScores</literal></term>
 788        <listitem>
 789         <para>
 790           Display a list of all installed packages with their calculated score
 791           used by the pkgProblemResolver. The description of the package
 792           is the same as described in <literal>Debug::pkgDepCache::Marker</literal>
 793         </para>
 794        </listitem>
 795      </varlistentry>
 796
 797      <varlistentry>
 798        <term><literal>Debug::sourceList</literal></term>
 799
 800        <listitem>
 801          <para>
 802            Print information about the vendors read from
 803            <filename>/etc/apt/vendors.list</filename>.
 804          </para>
 805        </listitem>
 806      </varlistentry>
 807
 808 <!-- 2009/07/11 Currently used nowhere. The corresponding code
 809 is commented.
 810      <varlistentry>
 811        <term><literal>Debug::Vendor</literal></term>
 812
 813        <listitem>
 814          <para>
 815            Print information about each vendor.
 816          </para>
 817        </listitem>
 818      </varlistentry>
 819 -->
 820    </variablelist>
 821  </refsect1>
 822
 823  <refsect1><title>Examples</title>
 824    <para>&configureindex; is a
 825    configuration file showing example values for all possible
 826    options.</para>
 827  </refsect1>
 828
 829  <refsect1><title>Files</title>
 830    <para><filename>/etc/apt/apt.conf</filename></para>
 831  </refsect1>
 832
 833  <refsect1><title>See Also</title>
 834    <para>&apt-cache;, &apt-config;<!-- ? reading apt.conf -->, &apt-preferences;.</para>
 835  </refsect1>
 836
 837  &manbugs;
 838
 839 </refentry>
 840