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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" [
5 <!ENTITY % aptent SYSTEM
"apt.ent">
13 &apt-author.jgunthorpe;
16 <firstname>Daniel
</firstname>
17 <surname>Burrows
</surname>
18 <contrib>Initial documentation of Debug::*.
</contrib>
19 <email>dburrows@debian.org
</email>
23 <!-- The last update date -->
24 <date>10 December
2008</date>
28 <refentrytitle>apt.conf
</refentrytitle>
29 <manvolnum>5</manvolnum>
30 <refmiscinfo class=
"manual">APT
</refmiscinfo>
33 <!-- Man page title -->
35 <refname>apt.conf
</refname>
36 <refpurpose>Configuration file for APT
</refpurpose>
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>
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
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>
65 <informalexample><programlisting>
72 </programlisting></informalexample>
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>
78 <informalexample><programlisting>
79 DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt";};
80 </programlisting></informalexample>
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>
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>
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 descendents are erased.
</para>
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>
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>
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>
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>
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>
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>
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>
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>
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>
152 <varlistentry><term>Build-Essential
</term>
153 <listitem><para>Defines which package(s) are considered essential build dependencies.
</para></listitem>
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>
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>
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>
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.
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>
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>
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>
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>
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::
<host
></literal> with the special keyword
<literal>DIRECT
</literal>
207 meaning to use no proxies. The
<envar>http_proxy
</envar> environment variable
208 will override all settings.
</para>
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>
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>
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>
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>
237 <para><literal>CaInfo
</literal> suboption specifies place of file that
238 holds info about trusted certificates.
239 <literal><host
>::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><host
>::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><host
>::Verify-Host
</literal> is corresponding per-host option.
246 <literal>SslCert
</literal> determines what certificate to use for client
247 authentication.
<literal><host
>::SslCert
</literal> is corresponding per-host option.
248 <literal>SslKey
</literal> determines what private key to use for client
249 authentication.
<literal><host
>::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><host
>::SslForceVersion
</literal> is corresponding per-host option.
253 </para></listitem></varlistentry>
255 <varlistentry><term>ftp
</term>
256 <listitem><para>FTP URIs; ftp::Proxy is the default proxy server to use. It is in the
257 standard form of
<literal>ftp://[[user][:pass]@]host[:port]/
</literal> and is
258 overridden by the
<envar>ftp_proxy
</envar> environment variable. To use a ftp
259 proxy you will have to set the
<literal>ftp::ProxyLogin
</literal> script in the
260 configuration file. This entry specifies the commands to send to tell
261 the proxy server what to connect to. Please see
262 &configureindex; for an example of
263 how to do this. The substitution variables available are
264 <literal>$(PROXY_USER)
</literal> <literal>$(PROXY_PASS)
</literal> <literal>$(SITE_USER)
</literal>
265 <literal>$(SITE_PASS)
</literal> <literal>$(SITE)
</literal> and
<literal>$(SITE_PORT)
</literal>
266 Each is taken from it's respective URI component.
</para>
268 <para>The option
<literal>timeout
</literal> sets the timeout timer used by the method,
269 this applies to all things including connection timeout and data timeout.
</para>
271 <para>Several settings are provided to control passive mode. Generally it is
272 safe to leave passive mode on, it works in nearly every environment.
273 However some situations require that passive mode be disabled and port
274 mode ftp used instead. This can be done globally, for connections that
275 go through a proxy or for a specific host (See the sample config file
276 for examples).
</para>
278 <para>It is possible to proxy FTP over HTTP by setting the
<envar>ftp_proxy
</envar>
279 environment variable to a http url - see the discussion of the http method
280 above for syntax. You cannot set this in the configuration file and it is
281 not recommended to use FTP over HTTP due to its low efficiency.
</para>
283 <para>The setting
<literal>ForceExtended
</literal> controls the use of RFC2428
284 <literal>EPSV
</literal> and
<literal>EPRT
</literal> commands. The default is false, which means
285 these commands are only used if the control connection is IPv6. Setting this
286 to true forces their use even on IPv4 connections. Note that most FTP servers
287 do not support RFC2428.
</para></listitem>
290 <varlistentry><term>cdrom
</term>
291 <listitem><para>CDROM URIs; the only setting for CDROM URIs is the mount point,
292 <literal>cdrom::Mount
</literal> which must be the mount point for the CDROM drive
293 as specified in
<filename>/etc/fstab
</filename>. It is possible to provide
294 alternate mount and unmount commands if your mount point cannot be listed
295 in the fstab (such as an SMB mount and old mount packages). The syntax
296 is to put
<literallayout>"/cdrom/"::Mount
"foo";
</literallayout> within
297 the cdrom block. It is important to have the trailing slash. Unmount
298 commands can be specified using UMount.
</para></listitem>
301 <varlistentry><term>gpgv
</term>
302 <listitem><para>GPGV URIs; the only option for GPGV URIs is the option to pass additional parameters to gpgv.
303 <literal>gpgv::Options
</literal> Additional options passed to gpgv.
307 <varlistentry><term>CompressionTypes
</term>
308 <listitem><para>List of compression types which are understood by the acquire methods.
309 Files like
<filename>Packages
</filename> can be available in various compression formats.
310 This list defines in which order the acquire methods will try to download these files.
311 Per default
<command>bzip2
</command> compressed files will be prefered over
312 <command>lzma
</command>,
<command>gzip
</command> and uncompressed files. The syntax for
313 the configuration fileentry is
314 <synopsis>Acquire::CompressionTypes::
<replaceable>FileExtension
</replaceable> "<replaceable>Methodname</replaceable>";
</synopsis>
315 e.g.
<synopsis>Acquire::CompressionTypes::bz2 "bzip2";
</synopsis>
316 Note that at runtime the
<literal>Dir::Bin::
<replaceable>Methodname
</replaceable></literal> will
317 be checked: If this setting exists the method will only be used if this file exists, e.g. for
318 the bzip2 method above (the inbuilt) setting is
<literallayout>Dir::Bin::bzip2 "/bin/bzip2";
</literallayout>
325 <refsect1><title>Directories
</title>
327 <para>The
<literal>Dir::State
</literal> section has directories that pertain to local
328 state information.
<literal>lists
</literal> is the directory to place downloaded
329 package lists in and
<literal>status
</literal> is the name of the dpkg status file.
330 <literal>preferences
</literal> is the name of the APT preferences file.
331 <literal>Dir::State
</literal> contains the default directory to prefix on all sub
332 items if they do not start with
<filename>/
</filename> or
<filename>./
</filename>.
</para>
334 <para><literal>Dir::Cache
</literal> contains locations pertaining to local cache
335 information, such as the two package caches
<literal>srcpkgcache
</literal> and
336 <literal>pkgcache
</literal> as well as the location to place downloaded archives,
337 <literal>Dir::Cache::archives
</literal>. Generation of caches can be turned off
338 by setting their names to be blank. This will slow down startup but
339 save disk space. It is probably preferred to turn off the pkgcache rather
340 than the srcpkgcache. Like
<literal>Dir::State
</literal> the default
341 directory is contained in
<literal>Dir::Cache
</literal></para>
343 <para><literal>Dir::Etc
</literal> contains the location of configuration files,
344 <literal>sourcelist
</literal> gives the location of the sourcelist and
345 <literal>main
</literal> is the default configuration file (setting has no effect,
346 unless it is done from the config file specified by
347 <envar>APT_CONFIG
</envar>).
</para>
349 <para>The
<literal>Dir::Parts
</literal> setting reads in all the config fragments in
350 lexical order from the directory specified. After this is done then the
351 main config file is loaded.
</para>
353 <para>Binary programs are pointed to by
<literal>Dir::Bin
</literal>.
<literal>Dir::Bin::Methods
</literal>
354 specifies the location of the method handlers and
<literal>gzip
</literal>,
355 <literal>bzip2
</literal>,
<literal>lzma
</literal>,
356 <literal>dpkg
</literal>,
<literal>apt-get
</literal> <literal>dpkg-source
</literal>
357 <literal>dpkg-buildpackage
</literal> and
<literal>apt-cache
</literal> specify the location
358 of the respective programs.
</para>
361 The configuration item
<literal>RootDir
</literal> has a special
362 meaning. If set, all paths in
<literal>Dir::
</literal> will be
363 relative to
<literal>RootDir
</literal>,
<emphasis>even paths that
364 are specified absolutely
</emphasis>. So, for instance, if
365 <literal>RootDir
</literal> is set to
366 <filename>/tmp/staging
</filename> and
367 <literal>Dir::State::status
</literal> is set to
368 <filename>/var/lib/dpkg/status
</filename>, then the status file
370 <filename>/tmp/staging/var/lib/dpkg/status
</filename>.
374 <refsect1><title>APT in DSelect
</title>
376 When APT is used as a
&dselect; method several configuration directives
377 control the default behaviour. These are in the
<literal>DSelect
</literal> section.
</para>
380 <varlistentry><term>Clean
</term>
381 <listitem><para>Cache Clean mode; this value may be one of always, prompt, auto,
382 pre-auto and never. always and prompt will remove all packages from
383 the cache after upgrading, prompt (the default) does so conditionally.
384 auto removes only those packages which are no longer downloadable
385 (replaced with a new version for instance). pre-auto performs this
386 action before downloading new packages.
</para></listitem>
389 <varlistentry><term>options
</term>
390 <listitem><para>The contents of this variable is passed to &apt-get; as command line
391 options when it is run for the install phase.
</para></listitem>
394 <varlistentry><term>Updateoptions
</term>
395 <listitem><para>The contents of this variable is passed to &apt-get; as command line
396 options when it is run for the update phase.
</para></listitem>
399 <varlistentry><term>PromptAfterUpdate
</term>
400 <listitem><para>If true the [U]pdate operation in
&dselect; will always prompt to continue.
401 The default is to prompt only on error.
</para></listitem>
406 <refsect1><title>How APT calls dpkg
</title>
407 <para>Several configuration directives control how APT invokes
&dpkg;. These are
408 in the
<literal>DPkg
</literal> section.
</para>
411 <varlistentry><term>options
</term>
412 <listitem><para>This is a list of options to pass to dpkg. The options must be specified
413 using the list notation and each list item is passed as a single argument
414 to
&dpkg;.
</para></listitem>
417 <varlistentry><term>Pre-Invoke
</term><term>Post-Invoke
</term>
418 <listitem><para>This is a list of shell commands to run before/after invoking
&dpkg;.
419 Like
<literal>options
</literal> this must be specified in list notation. The
420 commands are invoked in order using
<filename>/bin/sh
</filename>, should any
421 fail APT will abort.
</para></listitem>
424 <varlistentry><term>Pre-Install-Pkgs
</term>
425 <listitem><para>This is a list of shell commands to run before invoking dpkg. Like
426 <literal>options
</literal> this must be specified in list notation. The commands
427 are invoked in order using
<filename>/bin/sh
</filename>, should any fail APT
428 will abort. APT will pass to the commands on standard input the
429 filenames of all .deb files it is going to install, one per line.
</para>
431 <para>Version
2 of this protocol dumps more information, including the
432 protocol version, the APT configuration space and the packages, files
433 and versions being changed. Version
2 is enabled by setting
434 <literal>DPkg::Tools::options::cmd::Version
</literal> to
2.
<literal>cmd
</literal> is a
435 command given to
<literal>Pre-Install-Pkgs
</literal>.
</para></listitem>
438 <varlistentry><term>Run-Directory
</term>
439 <listitem><para>APT chdirs to this directory before invoking dpkg, the default is
440 <filename>/
</filename>.
</para></listitem>
443 <varlistentry><term>Build-options
</term>
444 <listitem><para>These options are passed to &dpkg-buildpackage; when compiling packages,
445 the default is to disable signing and produce all binaries.
</para></listitem>
451 <title>Periodic and Archives options
</title>
452 <para><literal>APT::Periodic
</literal> and
<literal>APT::Archives
</literal>
453 groups of options configure behavior of apt periodic updates, which is
454 done by
<literal>/etc/cron.daily/apt
</literal> script. See header of
455 this script for the brief documentation of these options.
460 <title>Debug options
</title>
462 Enabling options in the
<literal>Debug::
</literal> section will
463 cause debugging information to be sent to the standard error
464 stream of the program utilizing the
<literal>apt
</literal>
465 libraries, or enable special program modes that are primarily
466 useful for debugging the behavior of
<literal>apt
</literal>.
467 Most of these options are not interesting to a normal user, but a
473 <literal>Debug::pkgProblemResolver
</literal> enables output
474 about the decisions made by
475 <literal>dist-upgrade, upgrade, install, remove, purge
</literal>.
481 <literal>Debug::NoLocking
</literal> disables all file
482 locking. This can be used to run some operations (for
483 instance,
<literal>apt-get -s install
</literal>) as a
490 <literal>Debug::pkgDPkgPM
</literal> prints out the actual
491 command line each time that
<literal>apt
</literal> invokes
498 <literal>Debug::IdentCdrom
</literal> disables the inclusion
499 of statfs data in CDROM IDs.
<!-- TODO: provide a
500 motivating example, except I haven't a clue why you'd want
508 A full list of debugging options to apt follows.
513 <term><literal>Debug::Acquire::cdrom
</literal></term>
517 Print information related to accessing
518 <literal>cdrom://
</literal> sources.
524 <term><literal>Debug::Acquire::ftp
</literal></term>
528 Print information related to downloading packages using
535 <term><literal>Debug::Acquire::http
</literal></term>
539 Print information related to downloading packages using
546 <term><literal>Debug::Acquire::https
</literal></term>
550 Print information related to downloading packages using
557 <term><literal>Debug::Acquire::gpgv
</literal></term>
561 Print information related to verifying cryptographic
562 signatures using
<literal>gpg
</literal>.
568 <term><literal>Debug::aptcdrom
</literal></term>
572 Output information about the process of accessing
573 collections of packages stored on CD-ROMs.
579 <term><literal>Debug::BuildDeps
</literal></term>
582 Describes the process of resolving build-dependencies in
589 <term><literal>Debug::Hashes
</literal></term>
592 Output each cryptographic hash that is generated by the
593 <literal>apt
</literal> libraries.
599 <term><literal>Debug::IdentCDROM
</literal></term>
602 Do not include information from
<literal>statfs
</literal>,
603 namely the number of used and free blocks on the CD-ROM
604 filesystem, when generating an ID for a CD-ROM.
610 <term><literal>Debug::NoLocking
</literal></term>
613 Disable all file locking. For instance, this will allow
614 two instances of
<quote><literal>apt-get
615 update
</literal></quote> to run at the same time.
621 <term><literal>Debug::pkgAcquire
</literal></term>
625 Log when items are added to or removed from the global
632 <term><literal>Debug::pkgAcquire::Auth
</literal></term>
635 Output status messages and errors related to verifying
636 checksums and cryptographic signatures of downloaded files.
642 <term><literal>Debug::pkgAcquire::Diffs
</literal></term>
645 Output information about downloading and applying package
646 index list diffs, and errors relating to package index list
653 <term><literal>Debug::pkgAcquire::RRed
</literal></term>
657 Output information related to patching apt package lists
658 when downloading index diffs instead of full indices.
664 <term><literal>Debug::pkgAcquire::Worker
</literal></term>
668 Log all interactions with the sub-processes that actually
675 <term><literal>Debug::pkgAutoRemove
</literal></term>
679 Log events related to the automatically-installed status of
680 packages and to the removal of unused packages.
686 <term><literal>Debug::pkgDepCache::AutoInstall
</literal></term>
689 Generate debug messages describing which packages are being
690 automatically installed to resolve dependencies. This
691 corresponds to the initial auto-install pass performed in,
692 e.g.,
<literal>apt-get install
</literal>, and not to the
693 full
<literal>apt
</literal> dependency resolver; see
694 <literal>Debug::pkgProblemResolver
</literal> for that.
700 <term><literal>Debug::pkgDepCache::Marker
</literal></term>
703 Generate debug messages describing which package is marked
704 as keep/install/remove while the ProblemResolver does his work.
705 Each addition or deletion may trigger additional actions;
706 they are shown indented two additional space under the original entry.
707 The format for each line is
<literal>MarkKeep
</literal>,
708 <literal>MarkDelete
</literal> or
<literal>MarkInstall
</literal> followed by
709 <literal>package-name
<a.b.c -
> d.e.f | x.y.z
> (section)
</literal>
710 where
<literal>a.b.c
</literal> is the current version of the package,
711 <literal>d.e.f
</literal> is the version considered for installation and
712 <literal>x.y.z
</literal> is a newer version, but not considered for installation
713 (because of a low pin score). The later two can be omitted if there is none or if
714 it is the same version as the installed.
715 <literal>section
</literal> is the name of the section the package appears in.
720 <!-- Question: why doesn't this do anything? The code says it should. -->
722 <term><literal>Debug::pkgInitConfig
</literal></term>
725 Dump the default configuration to standard error on
732 <term><literal>Debug::pkgDPkgPM
</literal></term>
735 When invoking
&dpkg;, output the precise command line with
736 which it is being invoked, with arguments separated by a
737 single space character.
743 <term><literal>Debug::pkgDPkgProgressReporting
</literal></term>
746 Output all the data received from
&dpkg; on the status file
747 descriptor and any errors encountered while parsing it.
753 <term><literal>Debug::pkgOrderList
</literal></term>
757 Generate a trace of the algorithm that decides the order in
758 which
<literal>apt
</literal> should pass packages to
765 <term><literal>Debug::pkgPackageManager
</literal></term>
769 Output status messages tracing the steps performed when
776 <term><literal>Debug::pkgPolicy
</literal></term>
780 Output the priority of each package list on startup.
786 <term><literal>Debug::pkgProblemResolver
</literal></term>
790 Trace the execution of the dependency resolver (this
791 applies only to what happens when a complex dependency
792 problem is encountered).
798 <term><literal>Debug::pkgProblemResolver::ShowScores
</literal></term>
801 Display a list of all installed packages with their calculated score
802 used by the pkgProblemResolver. The description of the package
803 is the same as described in
<literal>Debug::pkgDepCache::Marker
</literal>
809 <term><literal>Debug::sourceList
</literal></term>
813 Print information about the vendors read from
814 <filename>/etc/apt/vendors.list
</filename>.
819 <!-- 2009/07/11 Currently used nowhere. The corresponding code
822 <term><literal>Debug::Vendor</literal></term>
826 Print information about each vendor.
834 <refsect1><title>Examples
</title>
835 <para>&configureindex; is a
836 configuration file showing example values for all possible
840 <refsect1><title>Files
</title>
842 <varlistentry><term><filename>/etc/apt/apt.conf
</filename></term>
843 <listitem><para>APT configuration file.
844 Configuration Item:
<literal>Dir::Etc::Main
</literal>.
</para></listitem>
847 <varlistentry><term><filename>/etc/apt/apt.conf.d/
</filename></term>
848 <listitem><para>APT configuration file fragments.
849 Configuration Item:
<literal>Dir::Etc::Parts
</literal>.
</para></listitem>
854 <refsect1><title>See Also
</title>
855 <para>&apt-cache;, &apt-config;
<!-- ? reading apt.conf -->, &apt-preferences;.
</para>