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  1. <?xml version="1.0" encoding="utf-8" standalone="no"?>
  2. <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  3. "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  4. <!ENTITY % aptent SYSTEM "apt.ent"> %aptent;
  5. <!ENTITY % aptverbatiment SYSTEM "apt-verbatim.ent"> %aptverbatiment;
  6. <!ENTITY % aptvendor SYSTEM "apt-vendor.ent"> %aptvendor;
  7. ]>
  8. <refentry>
  9. <refentryinfo>
  10. &apt-author.jgunthorpe;
  11. &apt-author.team;
  12. <author>
  13. &apt-name.dburrows;
  14. <contrib>Initial documentation of Debug::*.</contrib>
  15. <email>dburrows@debian.org</email>
  16. </author>
  17. &apt-email;
  18. &apt-product;
  19. <!-- The last update date -->
  20. <date>2019-04-04T00:00:00Z</date>
  21. </refentryinfo>
  22. <refmeta>
  23. <refentrytitle>apt.conf</refentrytitle>
  24. <manvolnum>5</manvolnum>
  25. <refmiscinfo class="manual">APT</refmiscinfo>
  26. </refmeta>
  27. <!-- Man page title -->
  28. <refnamediv>
  29. <refname>apt.conf</refname>
  30. <refpurpose>Configuration file for APT</refpurpose>
  31. </refnamediv>
  32. <refsect1><title>Description</title>
  33. <para><filename>/etc/apt/apt.conf</filename> is the main configuration
  34. file shared by all the tools in the APT suite of tools, though it is by
  35. no means the only place options can be set. The suite also shares a common
  36. command line parser to provide a uniform environment.</para>
  37. <orderedlist>
  38. <para>When an APT tool starts up it will read the configuration files
  39. in the following order:</para>
  40. <listitem><para>the file specified by the <envar>APT_CONFIG</envar>
  41. environment variable (if any)</para></listitem>
  42. <listitem><para>all files in <literal>Dir::Etc::Parts</literal> in
  43. alphanumeric ascending order which have either no or "<literal>conf</literal>"
  44. as filename extension and which only contain alphanumeric,
  45. hyphen (-), underscore (_) and period (.) characters.
  46. Otherwise APT will print a notice that it has ignored a file, unless that
  47. file matches a pattern in the <literal>Dir::Ignore-Files-Silently</literal>
  48. configuration list - in which case it will be silently ignored.</para></listitem>
  49. <listitem><para>the main configuration file specified by
  50. <literal>Dir::Etc::main</literal></para></listitem>
  51. <listitem><para>all options set in the binary specific configuration
  52. subtree are moved into the root of the tree.</para></listitem>
  53. <listitem><para>the command line options are applied to override the
  54. configuration directives or to load even more configuration files.</para></listitem>
  55. </orderedlist>
  56. </refsect1>
  57. <refsect1><title>Syntax</title>
  58. <para>The configuration file is organized in a tree with options organized into
  59. functional groups. Option specification is given with a double colon
  60. notation; for instance <literal>APT::Get::Assume-Yes</literal> is an option within
  61. the APT tool group, for the Get tool. Options do not inherit from their
  62. parent groups.</para>
  63. <para>Syntactically the configuration language is modeled after what the ISC tools
  64. such as bind and dhcp use. Lines starting with
  65. <literal>//</literal> are treated as comments (ignored), as well as all text
  66. between <literal>/*</literal> and <literal>*/</literal>, just like C/C++ comments.
  67. Each line is of the form
  68. <literal>APT::Get::Assume-Yes "true";</literal>.
  69. The quotation marks and trailing semicolon are required.
  70. The value must be on one line, and there is no kind of string concatenation.
  71. Values must not include backslashes or extra quotation marks.
  72. Option names are made up of alphanumeric characters and the characters "/-:._+".
  73. A new scope can be opened with curly braces, like this:</para>
  74. <informalexample><programlisting>
  75. APT {
  76. Get {
  77. Assume-Yes "true";
  78. Fix-Broken "true";
  79. };
  80. };
  81. </programlisting></informalexample>
  82. <para>with newlines placed to make it more readable. Lists can be created by
  83. opening a scope and including a single string enclosed in quotes followed by a
  84. semicolon. Multiple entries can be included, separated by a semicolon.</para>
  85. <informalexample><programlisting>
  86. DPkg::Pre-Install-Pkgs {"/usr/sbin/dpkg-preconfigure --apt";};
  87. </programlisting></informalexample>
  88. <para>In general the sample configuration file &configureindex;
  89. is a good guide for how it should look.</para>
  90. <para>Case is not significant in names of configuration items, so in the
  91. previous example you could use <literal>dpkg::pre-install-pkgs</literal>.</para>
  92. <para>Names for the configuration items are optional if a list is defined as can be seen in
  93. the <literal>DPkg::Pre-Install-Pkgs</literal> example above. If you don't specify a name a
  94. new entry will simply add a new option to the list. If you specify a name you can override
  95. the option in the same way as any other option by reassigning a new value to the option.</para>
  96. <para>Two special commands are defined: <literal>#include</literal> (which is
  97. deprecated and not supported by alternative implementations) and
  98. <literal>#clear</literal>. <literal>#include</literal> will include the
  99. given file, unless the filename ends in a slash, in which case the whole
  100. directory is included.
  101. <literal>#clear</literal> is used to erase a part of the configuration tree. The
  102. specified element and all its descendants are erased.
  103. (Note that these lines also need to end with a semicolon.)</para>
  104. <para>
  105. The <literal>#clear</literal> command is the only way to delete a list or
  106. a complete scope. Reopening a scope (or using the syntax described below
  107. with an appended <literal>::</literal>) will <emphasis>not</emphasis>
  108. override previously written entries. Options can only be overridden by
  109. addressing a new value to them - lists and scopes can't be overridden,
  110. only cleared.
  111. </para>
  112. <para>All of the APT tools take an -o option which allows an arbitrary configuration
  113. directive to be specified on the command line. The syntax is a full option
  114. name (<literal>APT::Get::Assume-Yes</literal> for instance) followed by an equals
  115. sign then the new value of the option. To append a new element to a list, add a
  116. trailing <literal>::</literal> to the name of the list.
  117. (As you might suspect, the scope syntax can't be used on the command line.)</para>
  118. <para>
  119. Note that appending items to a list using <literal>::</literal> only works
  120. for one item per line, and that you should not use it in combination with
  121. the scope syntax (which adds <literal>::</literal> implicitly). Using both
  122. syntaxes together will trigger a bug which some users unfortunately depend
  123. on: an option with the unusual name "<literal>::</literal>" which acts
  124. like every other option with a name. This introduces many problems; for
  125. one thing, users who write multiple lines in this
  126. <emphasis>wrong</emphasis> syntax in the hope of appending to a list will
  127. achieve the opposite, as only the last assignment for this option
  128. "<literal>::</literal>" will be used. Future versions of APT will raise
  129. errors and stop working if they encounter this misuse, so please correct
  130. such statements now while APT doesn't explicitly complain about them.
  131. </para>
  132. </refsect1>
  133. <refsect1><title>The APT Group</title>
  134. <para>This group of options controls general APT behavior as well as holding the
  135. options for all of the tools.</para>
  136. <variablelist>
  137. <varlistentry><term><option>Architecture</option></term>
  138. <listitem><para>System Architecture; sets the architecture to use when fetching files and
  139. parsing package lists. The internal default is the architecture apt was
  140. compiled for.</para></listitem>
  141. </varlistentry>
  142. <varlistentry><term><option>Architectures</option></term>
  143. <listitem><para>
  144. All Architectures the system supports. For instance, CPUs implementing
  145. the <literal>amd64</literal> (also called <literal>x86-64</literal>)
  146. instruction set are also able to execute binaries compiled for the
  147. <literal>i386</literal> (<literal>x86</literal>) instruction set. This
  148. list is used when fetching files and parsing package lists. The
  149. initial default is always the system's native architecture
  150. (<literal>APT::Architecture</literal>), and foreign architectures are
  151. added to the default list when they are registered via
  152. <command>dpkg --add-architecture</command>.
  153. </para></listitem>
  154. </varlistentry>
  155. <varlistentry><term><option>Compressor</option></term>
  156. <listitem><para>
  157. This scope defines which compression formats are supported, how compression
  158. and decompression can be performed if support for this format isn't built
  159. into apt directly and a cost-value indicating how costly it is to compress
  160. something in this format. As an example the following configuration stanza
  161. would allow apt to download and uncompress as well as create and store
  162. files with the low-cost <literal>.reversed</literal> file extension which
  163. it will pass to the command <command>rev</command> without additional
  164. commandline parameters for compression and uncompression:</para>
  165. <informalexample><programlisting>
  166. APT::Compressor::rev {
  167. Name "rev";
  168. Extension ".reversed";
  169. Binary "rev";
  170. CompressArg {};
  171. UncompressArg {};
  172. Cost "10";
  173. };
  174. </programlisting></informalexample>
  175. </listitem>
  176. </varlistentry>
  177. <varlistentry><term><option>Build-Profiles</option></term>
  178. <listitem><para>
  179. List of all build profiles enabled for build-dependency resolution,
  180. without the "<literal>profile.</literal>" namespace prefix.
  181. By default this list is empty. The <envar>DEB_BUILD_PROFILES</envar>
  182. as used by &dpkg-buildpackage; overrides the list notation.
  183. </para></listitem>
  184. </varlistentry>
  185. <varlistentry><term><option>Default-Release</option></term>
  186. <listitem><para>Default release to install packages from if more than one
  187. version is available. Contains release name, codename or release version. Examples: 'stable', 'testing',
  188. 'unstable', '&debian-stable-codename;', '&debian-testing-codename;', '4.0', '5.0*'. See also &apt-preferences;.</para></listitem>
  189. </varlistentry>
  190. <varlistentry><term><option>Ignore-Hold</option></term>
  191. <listitem><para>Ignore held packages; this global option causes the problem resolver to
  192. ignore held packages in its decision making.</para></listitem>
  193. </varlistentry>
  194. <varlistentry><term><option>Clean-Installed</option></term>
  195. <listitem><para>Defaults to on. When turned on the autoclean feature will remove any packages
  196. which can no longer be downloaded from the cache. If turned off then
  197. packages that are locally installed are also excluded from cleaning - but
  198. note that APT provides no direct means to reinstall them.</para></listitem>
  199. </varlistentry>
  200. <varlistentry><term><option>Immediate-Configure</option></term>
  201. <listitem><para>
  202. Defaults to on, which will cause APT to install essential and important
  203. packages as soon as possible in an install/upgrade operation, in order
  204. to limit the effect of a failing &dpkg; call. If this option is
  205. disabled, APT treats an important package in the same way as an extra
  206. package: between the unpacking of the package A and its configuration
  207. there can be many other unpack or configuration calls for other
  208. unrelated packages B, C etc. If these cause the &dpkg; call to fail
  209. (e.g. because package B's maintainer scripts generate an error), this
  210. results in a system state in which package A is unpacked but
  211. unconfigured - so any package depending on A is now no longer
  212. guaranteed to work, as its dependency on A is no longer satisfied.
  213. </para><para>
  214. The immediate configuration marker is also applied in the potentially
  215. problematic case of circular dependencies, since a dependency with the
  216. immediate flag is equivalent to a Pre-Dependency. In theory this allows
  217. APT to recognise a situation in which it is unable to perform immediate
  218. configuration, abort, and suggest to the user that the option should be
  219. temporarily deactivated in order to allow the operation to proceed.
  220. Note the use of the word "theory" here; in the real world this problem
  221. has rarely been encountered, in non-stable distribution versions, and
  222. was caused by wrong dependencies of the package in question or by a
  223. system in an already broken state; so you should not blindly disable
  224. this option, as the scenario mentioned above is not the only problem it
  225. can help to prevent in the first place.
  226. </para><para>
  227. Before a big operation like <literal>dist-upgrade</literal> is run
  228. with this option disabled you should try to explicitly
  229. <literal>install</literal> the package APT is unable to configure
  230. immediately; but please make sure you also report your problem to your
  231. distribution and to the APT team with the bug link below, so they can
  232. work on improving or correcting the upgrade process.
  233. </para></listitem>
  234. </varlistentry>
  235. <varlistentry><term><option>Force-LoopBreak</option></term>
  236. <listitem><para>
  237. Never enable this option unless you <emphasis>really</emphasis> know
  238. what you are doing. It permits APT to temporarily remove an essential
  239. package to break a Conflicts/Conflicts or Conflicts/Pre-Depends loop
  240. between two essential packages. <emphasis>Such a loop should never exist
  241. and is a grave bug</emphasis>. This option will work if the essential
  242. packages are not <command>tar</command>, <command>gzip</command>,
  243. <command>libc</command>, <command>dpkg</command>, <command>dash</command>
  244. or anything that those packages depend on.
  245. </para></listitem>
  246. </varlistentry>
  247. <varlistentry><term><option>Cache-Start</option></term><term><option>Cache-Grow</option></term><term><option>Cache-Limit</option></term>
  248. <listitem><para>APT uses since version 0.7.26 a resizable memory mapped cache file to store the available
  249. information. <literal>Cache-Start</literal> acts as a hint of the size the cache will grow to,
  250. and is therefore the amount of memory APT will request at startup. The default value is
  251. 20971520 bytes (~20 MB). Note that this amount of space needs to be available for APT;
  252. otherwise it will likely fail ungracefully, so for memory restricted devices this value should
  253. be lowered while on systems with a lot of configured sources it should be increased.
  254. <literal>Cache-Grow</literal> defines in bytes with the default of 1048576 (~1 MB) how much
  255. the cache size will be increased in the event the space defined by <literal>Cache-Start</literal>
  256. is not enough. This value will be applied again and again until either the cache is big
  257. enough to store all information or the size of the cache reaches the <literal>Cache-Limit</literal>.
  258. The default of <literal>Cache-Limit</literal> is 0 which stands for no limit.
  259. If <literal>Cache-Grow</literal> is set to 0 the automatic growth of the cache is disabled.
  260. </para></listitem>
  261. </varlistentry>
  262. <varlistentry><term><option>Build-Essential</option></term>
  263. <listitem><para>Defines which packages are considered essential build dependencies.</para></listitem>
  264. </varlistentry>
  265. <varlistentry><term><option>Get</option></term>
  266. <listitem><para>The Get subsection controls the &apt-get; tool; please see its
  267. documentation for more information about the options here.</para></listitem>
  268. </varlistentry>
  269. <varlistentry><term><option>Cache</option></term>
  270. <listitem><para>The Cache subsection controls the &apt-cache; tool; please see its
  271. documentation for more information about the options here.</para></listitem>
  272. </varlistentry>
  273. <varlistentry><term><option>CDROM</option></term>
  274. <listitem><para>The CDROM subsection controls the &apt-cdrom; tool; please see its
  275. documentation for more information about the options here.</para></listitem>
  276. </varlistentry>
  277. </variablelist>
  278. </refsect1>
  279. <refsect1><title>The Acquire Group</title>
  280. <para>The <literal>Acquire</literal> group of options controls the
  281. download of packages as well as the various "acquire methods" responsible
  282. for the download itself (see also &sources-list;).</para>
  283. <variablelist>
  284. <varlistentry><term><option>Check-Date</option></term>
  285. <listitem><para>
  286. Security related option defaulting to true, enabling time-related
  287. checks. Disabling it means that the machine's time cannot be
  288. trusted, and APT will hence disable all time-related checks,
  289. such as <option>Check-Valid-Until</option> and verifying that
  290. the Date field of a release file is not in the future.
  291. </para></listitem>
  292. </varlistentry>
  293. <varlistentry><term><option>Max-FutureTime</option></term>
  294. <listitem><para>Maximum time (in seconds) before its creation (as indicated
  295. by the <literal>Date</literal> header) that the <filename>Release</filename>
  296. file should be considered valid.
  297. The default value is <literal>10</literal>.
  298. Archive specific settings can be made by appending the label of the archive
  299. to the option name. Preferably, the same can be achieved for specific
  300. &sources-list; entries by using the <option>Date-Max-Future</option> option there.
  301. </para></listitem>
  302. </varlistentry>
  303. <varlistentry><term><option>Check-Valid-Until</option></term>
  304. <listitem><para>
  305. Security related option defaulting to true, as giving a Release file's
  306. validation an expiration date prevents replay attacks over a long
  307. timescale, and can also for example help users to identify mirrors
  308. that are no longer updated - but the feature depends on the
  309. correctness of the clock on the user system. Archive maintainers are
  310. encouraged to create Release files with the
  311. <literal>Valid-Until</literal> header, but if they don't or a
  312. stricter value is desired the <literal>Max-ValidTime</literal>
  313. option below can be used.
  314. The <option>Check-Valid-Until</option> option of &sources-list; entries should be
  315. preferred to disable the check selectively instead of using this global override.
  316. </para></listitem>
  317. </varlistentry>
  318. <varlistentry><term><option>Max-ValidTime</option></term>
  319. <listitem><para>Maximum time (in seconds) after its creation (as indicated
  320. by the <literal>Date</literal> header) that the <filename>Release</filename>
  321. file should be considered valid.
  322. If the Release file itself includes a <literal>Valid-Until</literal> header
  323. the earlier date of the two is used as the expiration date.
  324. The default value is <literal>0</literal> which stands for "valid forever".
  325. Archive specific settings can be made by appending the label of the archive
  326. to the option name. Preferably, the same can be achieved for specific
  327. &sources-list; entries by using the <option>Valid-Until-Max</option> option there.
  328. </para></listitem>
  329. </varlistentry>
  330. <varlistentry><term><option>Min-ValidTime</option></term>
  331. <listitem><para>Minimum time (in seconds) after its creation (as indicated
  332. by the <literal>Date</literal> header) that the <filename>Release</filename>
  333. file should be considered valid.
  334. Use this if you need to use a seldom updated (local) mirror of a more
  335. frequently updated archive with a <literal>Valid-Until</literal> header
  336. instead of completely disabling the expiration date checking.
  337. Archive specific settings can and should be used by appending the label of
  338. the archive to the option name. Preferably, the same can be achieved for specific
  339. &sources-list; entries by using the <option>Valid-Until-Min</option> option there.
  340. </para></listitem>
  341. </varlistentry>
  342. <varlistentry><term><option>AllowTLS</option></term>
  343. <listitem><para>
  344. Allow use of the internal TLS support in the http method. If set to false,
  345. this completely disables support for TLS in apt's own methods (excluding
  346. the curl-based https method). No TLS-related functions will be called
  347. anymore.
  348. </para></listitem>
  349. </varlistentry>
  350. <varlistentry><term><option>PDiffs</option></term>
  351. <listitem><para>Try to download deltas called <literal>PDiffs</literal> for
  352. indexes (like <filename>Packages</filename> files) instead of
  353. downloading whole ones. True by default. Preferably, this can be set
  354. for specific &sources-list; entries or index files by using the
  355. <option>PDiffs</option> option there.</para>
  356. <para>Two sub-options to limit the use of PDiffs are also available:
  357. <literal>FileLimit</literal> can be used to specify a maximum number of
  358. PDiff files should be downloaded to update a file. <literal>SizeLimit</literal>
  359. on the other hand is the maximum percentage of the size of all patches
  360. compared to the size of the targeted file. If one of these limits is
  361. exceeded the complete file is downloaded instead of the patches.
  362. </para></listitem>
  363. </varlistentry>
  364. <varlistentry><term><option>By-Hash</option></term>
  365. <listitem><para>Try to download indexes via an URI constructed from a
  366. hashsum of the expected file rather than downloaded via a well-known
  367. stable filename. True by default, but automatically disabled if the
  368. source indicates no support for it. Usage can be forced with the special
  369. value "force". Preferably, this can be set for specific &sources-list; entries
  370. or index files by using the <option>By-Hash</option> option there.
  371. </para></listitem>
  372. </varlistentry>
  373. <varlistentry><term><option>Queue-Mode</option></term>
  374. <listitem><para>Queuing mode; <literal>Queue-Mode</literal> can be one of <literal>host</literal> or
  375. <literal>access</literal> which determines how APT parallelizes outgoing
  376. connections. <literal>host</literal> means that one connection per target host
  377. will be opened, <literal>access</literal> means that one connection per URI type
  378. will be opened.</para></listitem>
  379. </varlistentry>
  380. <varlistentry><term><option>Retries</option></term>
  381. <listitem><para>Number of retries to perform. If this is non-zero APT will retry failed
  382. files the given number of times.</para></listitem>
  383. </varlistentry>
  384. <varlistentry><term><option>Source-Symlinks</option></term>
  385. <listitem><para>Use symlinks for source archives. If set to true then source archives will
  386. be symlinked when possible instead of copying. True is the default.</para></listitem>
  387. </varlistentry>
  388. <varlistentry><term><option>http</option> <option>https</option></term>
  389. <listitem><para>The options in these scopes configure APT's acquire transports for the protocols
  390. HTTP and HTTPS and are documented in the &apt-transport-http; and &apt-transport-https;
  391. manpages respectively.</para></listitem>
  392. </varlistentry>
  393. <varlistentry><term><option>ftp</option></term>
  394. <listitem><para>
  395. <literal>ftp::Proxy</literal> sets the default proxy to use for FTP URIs.
  396. It is in the standard form of <literal>ftp://[[user][:pass]@]host[:port]/</literal>.
  397. Per host proxies can also be specified by using the form
  398. <literal>ftp::Proxy::&lt;host&gt;</literal> with the special keyword <literal>DIRECT</literal>
  399. meaning to use no proxies. If no one of the above settings is specified,
  400. <envar>ftp_proxy</envar> environment variable
  401. will be used. To use an FTP
  402. proxy you will have to set the <literal>ftp::ProxyLogin</literal> script in the
  403. configuration file. This entry specifies the commands to send to tell
  404. the proxy server what to connect to. Please see
  405. &configureindex; for an example of
  406. how to do this. The substitution variables representing the corresponding
  407. URI component are <literal>$(PROXY_USER)</literal>,
  408. <literal>$(PROXY_PASS)</literal>, <literal>$(SITE_USER)</literal>,
  409. <literal>$(SITE_PASS)</literal>, <literal>$(SITE)</literal> and
  410. <literal>$(SITE_PORT)</literal>.</para>
  411. <para>The option <literal>timeout</literal> sets the timeout timer used by the method;
  412. this value applies to the connection as well as the data timeout.</para>
  413. <para>Several settings are provided to control passive mode. Generally it is
  414. safe to leave passive mode on; it works in nearly every environment.
  415. However, some situations require that passive mode be disabled and port
  416. mode FTP used instead. This can be done globally or for connections that
  417. go through a proxy or for a specific host (see the sample config file
  418. for examples).</para>
  419. <para>It is possible to proxy FTP over HTTP by setting the <envar>ftp_proxy</envar>
  420. environment variable to an HTTP URL - see the discussion of the http method
  421. above for syntax. You cannot set this in the configuration file and it is
  422. not recommended to use FTP over HTTP due to its low efficiency.</para>
  423. <para>The setting <literal>ForceExtended</literal> controls the use of RFC2428
  424. <literal>EPSV</literal> and <literal>EPRT</literal> commands. The default is false, which means
  425. these commands are only used if the control connection is IPv6. Setting this
  426. to true forces their use even on IPv4 connections. Note that most FTP servers
  427. do not support RFC2428.</para></listitem>
  428. </varlistentry>
  429. <varlistentry><term><option>cdrom</option></term>
  430. <listitem><para>
  431. For URIs using the <literal>cdrom</literal> method, the only configurable
  432. option is the mount point, <literal>cdrom::Mount</literal>, which must be
  433. the mount point for the CD-ROM (or DVD, or whatever) drive as specified in
  434. <filename>/etc/fstab</filename>. It is possible to provide alternate mount
  435. and unmount commands if your mount point cannot be listed in the fstab.
  436. The syntax is to put <literallayout>/cdrom/::Mount "foo";</literallayout> within
  437. the <literal>cdrom</literal> block. It is important to have the trailing slash.
  438. Unmount commands can be specified using UMount.
  439. </para></listitem>
  440. </varlistentry>
  441. <varlistentry><term><option>gpgv</option></term>
  442. <listitem><para>
  443. For GPGV URIs the only configurable option is <literal>gpgv::Options</literal>,
  444. which passes additional parameters to gpgv.
  445. </para></listitem>
  446. </varlistentry>
  447. <varlistentry><term><option>CompressionTypes</option></term>
  448. <listitem><para>List of compression types which are understood by the acquire methods.
  449. Files like <filename>Packages</filename> can be available in various compression formats.
  450. By default the acquire methods can decompress and recompress many common formats like <command>xz</command> and
  451. <command>gzip</command>; with this scope the supported formats can be queried, modified
  452. as well as support for more formats added (see also <option>APT::Compressor</option>). The syntax for this is:
  453. <synopsis>Acquire::CompressionTypes::<replaceable>FileExtension</replaceable> "<replaceable>Methodname</replaceable>";</synopsis>
  454. </para><para>Also, the <literal>Order</literal> subgroup can be used to define in which order
  455. the acquire system will try to download the compressed files. The acquire system will try the first
  456. and proceed with the next compression type in this list on error, so to prefer one over the other type
  457. simply add the preferred type first - types not already added will be implicitly appended
  458. to the end of the list, so e.g. <synopsis>Acquire::CompressionTypes::Order:: "gz";</synopsis> can
  459. be used to prefer <command>gzip</command> compressed files over all other compression formats.
  460. If <command>xz</command> should be preferred over <command>gzip</command> and <command>bzip2</command> the
  461. configure setting should look like this: <synopsis>Acquire::CompressionTypes::Order { "xz"; "gz"; };</synopsis>
  462. It is not needed to add <literal>bz2</literal> to the list explicitly as it will be added automatically.</para>
  463. <para>Note that the
  464. <literal>Dir::Bin::<replaceable>Methodname</replaceable></literal>
  465. will be checked at run time. If this option has been set and support for
  466. this format isn't directly built into apt, the method will only be used if
  467. this file exists; e.g. for the <literal>bzip2</literal> method (the
  468. inbuilt) setting is: <literallayout>Dir::Bin::bzip2 "/bin/bzip2";</literallayout>
  469. Note also that list entries specified on the command line will be added at the end of the list
  470. specified in the configuration files, but before the default entries. To prefer a type in this case
  471. over the ones specified in the configuration files you can set the option direct - not in list style.
  472. This will not override the defined list; it will only prefix the list with this type.</para>
  473. <para>The special type <literal>uncompressed</literal> can be used to give uncompressed files a
  474. preference, but note that most archives don't provide uncompressed files so this is mostly only
  475. usable for local mirrors.</para></listitem>
  476. </varlistentry>
  477. <varlistentry><term><option>GzipIndexes</option></term>
  478. <listitem><para>
  479. When downloading <literal>gzip</literal> compressed indexes (Packages, Sources, or
  480. Translations), keep them gzip compressed locally instead of unpacking
  481. them. This saves quite a lot of disk space at the expense of more CPU
  482. requirements when building the local package caches. False by default.
  483. </para></listitem>
  484. </varlistentry>
  485. <varlistentry><term><option>Languages</option></term>
  486. <listitem><para>The Languages subsection controls which <filename>Translation</filename> files are downloaded
  487. and in which order APT tries to display the description-translations. APT will try to display the first
  488. available description in the language which is listed first. Languages can be defined with their
  489. short or long language codes. Note that not all archives provide <filename>Translation</filename>
  490. files for every language - the long language codes are especially rare.</para>
  491. <para>The default list includes "environment" and "en". "<literal>environment</literal>" has a special meaning here:
  492. it will be replaced at runtime with the language codes extracted from the <literal>LC_MESSAGES</literal> environment variable.
  493. It will also ensure that these codes are not included twice in the list. If <literal>LC_MESSAGES</literal>
  494. is set to "C" only the <filename>Translation-en</filename> file (if available) will be used.
  495. To force APT to use no Translation file use the setting <literal>Acquire::Languages=none</literal>. "<literal>none</literal>"
  496. is another special meaning code which will stop the search for a suitable <filename>Translation</filename> file.
  497. This tells APT to download these translations too, without actually
  498. using them unless the environment specifies the languages. So the
  499. following example configuration will result in the order "en, de" in an
  500. English locale or "de, en" in a German one. Note that "fr" is
  501. downloaded, but not used unless APT is used in a French locale (where
  502. the order would be "fr, de, en").
  503. <programlisting>Acquire::Languages { "environment"; "de"; "en"; "none"; "fr"; };</programlisting></para>
  504. <para>Note: To prevent problems resulting from APT being executed in different environments
  505. (e.g. by different users or by other programs) all Translation files which are found in
  506. <filename>/var/lib/apt/lists/</filename> will be added to the end of the list
  507. (after an implicit "<literal>none</literal>").</para>
  508. </listitem>
  509. </varlistentry>
  510. <varlistentry><term><option>ForceIPv4</option></term>
  511. <listitem><para>
  512. When downloading, force to use only the IPv4 protocol.
  513. </para></listitem>
  514. </varlistentry>
  515. <varlistentry><term><option>ForceIPv6</option></term>
  516. <listitem><para>
  517. When downloading, force to use only the IPv6 protocol.
  518. </para></listitem>
  519. </varlistentry>
  520. <varlistentry><term><option>MaxReleaseFileSize</option></term>
  521. <listitem><para>
  522. The maximum file size of Release/Release.gpg/InRelease files.
  523. The default is 10MB.
  524. </para></listitem>
  525. </varlistentry>
  526. <varlistentry><term><option>EnableSrvRecords</option></term>
  527. <listitem><para>
  528. This option controls if apt will use the DNS SRV server record
  529. as specified in RFC 2782 to select an alternative server to
  530. connect to.
  531. The default is "true".
  532. </para></listitem>
  533. </varlistentry>
  534. <varlistentry><term><option>AllowInsecureRepositories</option></term>
  535. <listitem><para>
  536. Allow update operations to load data files from
  537. repositories without sufficient security information.
  538. The default value is "<literal>false</literal>".
  539. Concept, implications as well as alternatives are detailed in &apt-secure;.
  540. </para></listitem>
  541. </varlistentry>
  542. <varlistentry><term><option>AllowWeakRepositories</option></term>
  543. <listitem><para>
  544. Allow update operations to load data files from
  545. repositories which provide security information, but these
  546. are deemed no longer cryptographically strong enough.
  547. The default value is "<literal>false</literal>".
  548. Concept, implications as well as alternatives are detailed in &apt-secure;.
  549. </para></listitem>
  550. </varlistentry>
  551. <varlistentry><term><option>AllowDowngradeToInsecureRepositories</option></term>
  552. <listitem><para>
  553. Allow that a repository that was previously gpg signed to become
  554. unsigned during an update operation. When there is no valid signature
  555. for a previously trusted repository apt will refuse the update. This
  556. option can be used to override this protection. You almost certainly
  557. never want to enable this. The default is <literal>false</literal>.
  558. Concept, implications as well as alternatives are detailed in &apt-secure;.
  559. </para></listitem>
  560. </varlistentry>
  561. <varlistentry><term><option>Changelogs::URI</option> scope</term>
  562. <listitem><para>
  563. Acquiring changelogs can only be done if an URI is known from where to get them.
  564. Preferable the Release file indicates this in a 'Changelogs' field. If this isn't
  565. available the Label/Origin field of the Release file is used to check if a
  566. <literal>Acquire::Changelogs::URI::Label::<replaceable>LABEL</replaceable></literal> or
  567. <literal>Acquire::Changelogs::URI::Origin::<replaceable>ORIGIN</replaceable></literal> option
  568. exists and if so this value is taken. The value in the Release file can be overridden
  569. with <literal>Acquire::Changelogs::URI::Override::Label::<replaceable>LABEL</replaceable></literal>
  570. or <literal>Acquire::Changelogs::URI::Override::Origin::<replaceable>ORIGIN</replaceable></literal>.
  571. The value should be a normal URI to a text file, except that package specific data is
  572. replaced with the placeholder <literal>@CHANGEPATH@</literal>. The
  573. value for it is: 1. if the package is from a component (e.g. <literal>main</literal>)
  574. this is the first part otherwise it is omitted, 2. the first letter of source package name,
  575. except if the source package name starts with '<literal>lib</literal>' in which case it will
  576. be the first four letters. 3. The complete source package name. 4. the complete name again and
  577. 5. the source version.
  578. The first (if present), second, third and fourth part are separated by a slash ('<literal>/</literal>')
  579. and between the fourth and fifth part is an underscore ('<literal>_</literal>').
  580. The special value '<literal>no</literal>' is available for this option indicating that
  581. this source can't be used to acquire changelog files from. Another source will be tried
  582. if available in this case.
  583. </para></listitem>
  584. </varlistentry>
  585. </variablelist>
  586. </refsect1>
  587. <refsect1><title>Binary specific configuration</title>
  588. <para>Especially with the introduction of the <command>apt</command> binary
  589. it can be useful to set certain options only for a specific binary as
  590. even options which look like they would effect only a certain binary like
  591. <option>APT::Get::Show-Versions</option> effect
  592. <command>apt-get</command> as well as <command>apt</command>.
  593. </para>
  594. <para>Setting an option for a specific binary only can be achieved by
  595. setting the option inside the
  596. <option>Binary::<replaceable>specific-binary</replaceable></option>
  597. scope. Setting the option <option>APT::Get::Show-Versions</option> for
  598. the <command>apt</command> only can e.g. by done by setting
  599. <option>Binary::apt::APT::Get::Show-Versions</option> instead.</para>
  600. <para>Note that as seen in the DESCRIPTION section further above you can't
  601. set binary-specific options on the commandline itself nor in
  602. configuration files loaded via the commandline.</para>
  603. </refsect1>
  604. <refsect1><title>Directories</title>
  605. <para>The <literal>Dir::State</literal> section has directories that pertain to local
  606. state information. <literal>lists</literal> is the directory to place downloaded
  607. package lists in and <literal>status</literal> is the name of the &dpkg; status file.
  608. <literal>preferences</literal> is the name of the APT <filename>preferences</filename> file.
  609. <literal>Dir::State</literal> contains the default directory to prefix on all
  610. sub-items if they do not start with <filename>/</filename> or <filename>./</filename>.</para>
  611. <para><literal>Dir::Cache</literal> contains locations pertaining to local cache
  612. information, such as the two package caches <literal>srcpkgcache</literal> and
  613. <literal>pkgcache</literal> as well as the location to place downloaded archives,
  614. <literal>Dir::Cache::archives</literal>. Generation of caches can be turned off
  615. by setting <literal>pkgcache</literal> or <literal>srcpkgcache</literal> to
  616. <literal>""</literal>. This will slow down startup but save disk space. It
  617. is probably preferable to turn off the pkgcache rather than the srcpkgcache.
  618. Like <literal>Dir::State</literal> the default directory is contained in
  619. <literal>Dir::Cache</literal></para>
  620. <para><literal>Dir::Etc</literal> contains the location of configuration files,
  621. <literal>sourcelist</literal> gives the location of the sourcelist and
  622. <literal>main</literal> is the default configuration file (setting has no effect,
  623. unless it is done from the config file specified by
  624. <envar>APT_CONFIG</envar>).</para>
  625. <para>The <literal>Dir::Parts</literal> setting reads in all the config fragments in
  626. lexical order from the directory specified. After this is done then the
  627. main config file is loaded.</para>
  628. <para>Binary programs are pointed to by <literal>Dir::Bin</literal>. <literal>Dir::Bin::Methods</literal>
  629. specifies the location of the method handlers and <literal>gzip</literal>,
  630. <literal>bzip2</literal>, <literal>lzma</literal>,
  631. <literal>dpkg</literal>, <literal>apt-get</literal> <literal>dpkg-source</literal>
  632. <literal>dpkg-buildpackage</literal> and <literal>apt-cache</literal> specify the location
  633. of the respective programs.</para>
  634. <para>
  635. The configuration item <literal>RootDir</literal> has a special
  636. meaning. If set, all paths will be
  637. relative to <literal>RootDir</literal>, <emphasis>even paths that
  638. are specified absolutely</emphasis>. So, for instance, if
  639. <literal>RootDir</literal> is set to
  640. <filename>/tmp/staging</filename> and
  641. <literal>Dir::State::status</literal> is set to
  642. <filename>/var/lib/dpkg/status</filename>, then the status file
  643. will be looked up in
  644. <filename>/tmp/staging/var/lib/dpkg/status</filename>.
  645. If you want to prefix only relative paths, set <literal>Dir</literal> instead.
  646. </para>
  647. <para>
  648. The <literal>Ignore-Files-Silently</literal> list can be used to specify
  649. which files APT should silently ignore while parsing the files in the
  650. fragment directories. Per default a file which ends with <literal>.disabled</literal>,
  651. <literal>~</literal>, <literal>.bak</literal> or <literal>.dpkg-[a-z]+</literal>
  652. is silently ignored. As seen in the last default value these patterns can use regular
  653. expression syntax.
  654. </para>
  655. </refsect1>
  656. <refsect1><title>APT in DSelect</title>
  657. <para>
  658. When APT is used as a &dselect; method several configuration directives
  659. control the default behavior. These are in the <literal>DSelect</literal> section.</para>
  660. <variablelist>
  661. <varlistentry><term><option>Clean</option></term>
  662. <listitem><para>Cache Clean mode; this value may be one of
  663. <literal>always</literal>, <literal>prompt</literal>,
  664. <literal>auto</literal>, <literal>pre-auto</literal> and
  665. <literal>never</literal>.
  666. <literal>always</literal> and <literal>prompt</literal> will remove
  667. all packages from the cache after upgrading, <literal>prompt</literal>
  668. (the default) does so conditionally.
  669. <literal>auto</literal> removes only those packages which are no longer
  670. downloadable (replaced with a new version for instance).
  671. <literal>pre-auto</literal> performs this action before downloading
  672. new packages.</para></listitem>
  673. </varlistentry>
  674. <varlistentry><term><option>options</option></term>
  675. <listitem><para>The contents of this variable are passed to &apt-get; as command line
  676. options when it is run for the install phase.</para></listitem>
  677. </varlistentry>
  678. <varlistentry><term><option>Updateoptions</option></term>
  679. <listitem><para>The contents of this variable are passed to &apt-get; as command line
  680. options when it is run for the update phase.</para></listitem>
  681. </varlistentry>
  682. <varlistentry><term><option>PromptAfterUpdate</option></term>
  683. <listitem><para>If true the [U]pdate operation in &dselect; will always prompt to continue.
  684. The default is to prompt only on error.</para></listitem>
  685. </varlistentry>
  686. </variablelist>
  687. </refsect1>
  688. <refsect1><title>How APT calls &dpkg;</title>
  689. <para>Several configuration directives control how APT invokes &dpkg;. These are
  690. in the <literal>DPkg</literal> section.</para>
  691. <variablelist>
  692. <varlistentry><term><option>options</option></term>
  693. <listitem><para>This is a list of options to pass to &dpkg;. The options must be specified
  694. using the list notation and each list item is passed as a single argument
  695. to &dpkg;.</para></listitem>
  696. </varlistentry>
  697. <varlistentry><term><option>Path</option></term>
  698. <listitem><para>This is a string that defines the <envar>PATH</envar>
  699. environment variable used when running dpkg. It may be set to any
  700. valid value of that environment variable; or the empty string, in
  701. which case the variable is not changed.</para></listitem>
  702. </varlistentry>
  703. <varlistentry><term><option>Pre-Invoke</option></term><term><option>Post-Invoke</option></term>
  704. <listitem><para>This is a list of shell commands to run before/after invoking &dpkg;.
  705. Like <literal>options</literal> this must be specified in list notation. The
  706. commands are invoked in order using <filename>/bin/sh</filename>; should any
  707. fail APT will abort.</para></listitem>
  708. </varlistentry>
  709. <varlistentry><term><option>Pre-Install-Pkgs</option></term>
  710. <listitem><para>This is a list of shell commands to run before invoking &dpkg;. Like
  711. <literal>options</literal> this must be specified in list notation. The commands
  712. are invoked in order using <filename>/bin/sh</filename>; should any fail APT
  713. will abort. APT will pass the filenames of all .deb files it is going to
  714. install to the commands, one per line on the requested file descriptor, defaulting
  715. to standard input.</para>
  716. <para>Version 2 of this protocol sends more information through the requested
  717. file descriptor: a line with the text <literal>VERSION 2</literal>,
  718. the APT configuration space, and a list of package actions with filename
  719. and version information.</para>
  720. <para>Each configuration directive line has the form
  721. <literal>key=value</literal>. Special characters (equal signs, newlines,
  722. nonprintable characters, quotation marks, and percent signs in
  723. <literal>key</literal> and newlines, nonprintable characters, and percent
  724. signs in <literal>value</literal>) are %-encoded. Lists are represented
  725. by multiple <literal>key::=value</literal> lines with the same key. The
  726. configuration section ends with a blank line.</para>
  727. <para>Package action lines consist of five fields in Version 2: package
  728. name (without architecture qualification even if foreign), old version,
  729. direction of version change (&lt; for upgrades, &gt; for downgrades, = for
  730. no change), new version, action. The version fields are "-" for no version
  731. at all (for example when installing a package for the first time; no
  732. version is treated as earlier than any real version, so that is an
  733. upgrade, indicated as <literal>- &lt; 1.23.4</literal>). The action field
  734. is "**CONFIGURE**" if the package is being configured, "**REMOVE**" if it
  735. is being removed, or the filename of a .deb file if it is being
  736. unpacked.</para>
  737. <para>In Version 3 after each version field follows the architecture
  738. of this version, which is "-" if there is no version, and a field showing
  739. the MultiArch type "same", "foreign", "allowed" or "none". Note that "none"
  740. is an incorrect typename which is just kept to remain compatible, it
  741. should be read as "no" and users are encouraged to support both.</para>
  742. <para>The version of the protocol to be used for the command
  743. <literal><replaceable>cmd</replaceable></literal> can be chosen by setting
  744. <literal>DPkg::Tools::options::<replaceable>cmd</replaceable>::Version</literal>
  745. accordingly, the default being version 1. If APT isn't supporting the requested
  746. version it will send the information in the highest version it has support for instead.
  747. </para>
  748. <para>The file descriptor to be used to send the information can be requested with
  749. <literal>DPkg::Tools::options::<replaceable>cmd</replaceable>::InfoFD</literal>
  750. which defaults to <literal>0</literal> for standard input and is available since
  751. version 0.9.11. Support for the option can be detected by looking for the environment
  752. variable <envar>APT_HOOK_INFO_FD</envar> which contains the number of the used
  753. file descriptor as a confirmation.</para>
  754. </listitem>
  755. </varlistentry>
  756. <varlistentry><term><option>Run-Directory</option></term>
  757. <listitem><para>APT chdirs to this directory before invoking &dpkg;, the default is
  758. <filename>/</filename>.</para></listitem>
  759. </varlistentry>
  760. <varlistentry><term><option>Build-options</option></term>
  761. <listitem><para>These options are passed to &dpkg-buildpackage; when compiling packages;
  762. the default is to disable signing and produce all binaries.</para></listitem>
  763. </varlistentry>
  764. <varlistentry><term><option>DPkg::ConfigurePending</option></term>
  765. <listitem><para>If this option is set APT will call <command>dpkg --configure --pending</command>
  766. to let &dpkg; handle all required configurations and triggers. This option is activated by default,
  767. but deactivating it could be useful if you want to run APT multiple times in a row - e.g. in an installer.
  768. In this scenario you could deactivate this option in all but the last run.</para></listitem>
  769. </varlistentry>
  770. </variablelist>
  771. </refsect1>
  772. <refsect1>
  773. <title>Periodic and Archives options</title>
  774. <para><literal>APT::Periodic</literal> and <literal>APT::Archives</literal>
  775. groups of options configure behavior of apt periodic updates, which is
  776. done by the <literal>/usr/lib/apt/apt.systemd.daily</literal> script. See the top of
  777. this script for the brief documentation of these options.
  778. </para>
  779. </refsect1>
  780. <refsect1>
  781. <title>Debug options</title>
  782. <para>
  783. Enabling options in the <literal>Debug::</literal> section will
  784. cause debugging information to be sent to the standard error
  785. stream of the program utilizing the <literal>apt</literal>
  786. libraries, or enable special program modes that are primarily
  787. useful for debugging the behavior of <literal>apt</literal>.
  788. Most of these options are not interesting to a normal user, but a
  789. few may be:
  790. <itemizedlist>
  791. <listitem>
  792. <para>
  793. <literal>Debug::pkgProblemResolver</literal> enables output
  794. about the decisions made by
  795. <literal>dist-upgrade, upgrade, install, remove, purge</literal>.
  796. </para>
  797. </listitem>
  798. <listitem>
  799. <para>
  800. <literal>Debug::NoLocking</literal> disables all file
  801. locking. This can be used to run some operations (for
  802. instance, <literal>apt-get -s install</literal>) as a
  803. non-root user.
  804. </para>
  805. </listitem>
  806. <listitem>
  807. <para>
  808. <literal>Debug::pkgDPkgPM</literal> prints out the actual
  809. command line each time that <literal>apt</literal> invokes
  810. &dpkg;.
  811. </para>
  812. </listitem>
  813. <listitem>
  814. <para>
  815. <literal>Debug::IdentCdrom</literal> disables the inclusion
  816. of statfs data in CD-ROM IDs. <!-- TODO: provide a
  817. motivating example, except I haven't a clue why you'd want
  818. to do this. -->
  819. </para>
  820. </listitem>
  821. </itemizedlist>
  822. </para>
  823. <para>
  824. A full list of debugging options to apt follows.
  825. </para>
  826. <variablelist>
  827. <varlistentry>
  828. <term><option>Debug::Acquire::cdrom</option></term>
  829. <listitem>
  830. <para>
  831. Print information related to accessing
  832. <literal>cdrom://</literal> sources.
  833. </para>
  834. </listitem>
  835. </varlistentry>
  836. <varlistentry>
  837. <term><option>Debug::Acquire::ftp</option></term>
  838. <listitem>
  839. <para>
  840. Print information related to downloading packages using
  841. FTP.
  842. </para>
  843. </listitem>
  844. </varlistentry>
  845. <varlistentry>
  846. <term><option>Debug::Acquire::http</option></term>
  847. <listitem>
  848. <para>
  849. Print information related to downloading packages using
  850. HTTP.
  851. </para>
  852. </listitem>
  853. </varlistentry>
  854. <varlistentry>
  855. <term><option>Debug::Acquire::https</option></term>
  856. <listitem>
  857. <para>
  858. Print information related to downloading packages using
  859. HTTPS.
  860. </para>
  861. </listitem>
  862. </varlistentry>
  863. <varlistentry>
  864. <term><option>Debug::Acquire::gpgv</option></term>
  865. <listitem>
  866. <para>
  867. Print information related to verifying cryptographic
  868. signatures using <literal>gpg</literal>.
  869. </para>
  870. </listitem>
  871. </varlistentry>
  872. <varlistentry>
  873. <term><option>Debug::aptcdrom</option></term>
  874. <listitem>
  875. <para>
  876. Output information about the process of accessing
  877. collections of packages stored on CD-ROMs.
  878. </para>
  879. </listitem>
  880. </varlistentry>
  881. <varlistentry>
  882. <term><option>Debug::BuildDeps</option></term>
  883. <listitem>
  884. <para>
  885. Describes the process of resolving build-dependencies in
  886. &apt-get;.
  887. </para>
  888. </listitem>
  889. </varlistentry>
  890. <varlistentry>
  891. <term><option>Debug::Hashes</option></term>
  892. <listitem>
  893. <para>
  894. Output each cryptographic hash that is generated by the
  895. <literal>apt</literal> libraries.
  896. </para>
  897. </listitem>
  898. </varlistentry>
  899. <varlistentry>
  900. <term><option>Debug::IdentCDROM</option></term>
  901. <listitem>
  902. <para>
  903. Do not include information from <literal>statfs</literal>,
  904. namely the number of used and free blocks on the CD-ROM
  905. filesystem, when generating an ID for a CD-ROM.
  906. </para>
  907. </listitem>
  908. </varlistentry>
  909. <varlistentry>
  910. <term><option>Debug::NoLocking</option></term>
  911. <listitem>
  912. <para>
  913. Disable all file locking. For instance, this will allow
  914. two instances of <quote><literal>apt-get
  915. update</literal></quote> to run at the same time.
  916. </para>
  917. </listitem>
  918. </varlistentry>
  919. <varlistentry>
  920. <term><option>Debug::pkgAcquire</option></term>
  921. <listitem>
  922. <para>
  923. Log when items are added to or removed from the global
  924. download queue.
  925. </para>
  926. </listitem>
  927. </varlistentry>
  928. <varlistentry>
  929. <term><option>Debug::pkgAcquire::Auth</option></term>
  930. <listitem>
  931. <para>
  932. Output status messages and errors related to verifying
  933. checksums and cryptographic signatures of downloaded files.
  934. </para>
  935. </listitem>
  936. </varlistentry>
  937. <varlistentry>
  938. <term><option>Debug::pkgAcquire::Diffs</option></term>
  939. <listitem>
  940. <para>
  941. Output information about downloading and applying package
  942. index list diffs, and errors relating to package index list
  943. diffs.
  944. </para>
  945. </listitem>
  946. </varlistentry>
  947. <varlistentry>
  948. <term><option>Debug::pkgAcquire::RRed</option></term>
  949. <listitem>
  950. <para>
  951. Output information related to patching apt package lists
  952. when downloading index diffs instead of full indices.
  953. </para>
  954. </listitem>
  955. </varlistentry>
  956. <varlistentry>
  957. <term><option>Debug::pkgAcquire::Worker</option></term>
  958. <listitem>
  959. <para>
  960. Log all interactions with the sub-processes that actually
  961. perform downloads.
  962. </para>
  963. </listitem>
  964. </varlistentry>
  965. <varlistentry>
  966. <term><option>Debug::pkgAutoRemove</option></term>
  967. <listitem>
  968. <para>
  969. Log events related to the automatically-installed status of
  970. packages and to the removal of unused packages.
  971. </para>
  972. </listitem>
  973. </varlistentry>
  974. <varlistentry>
  975. <term><option>Debug::pkgDepCache::AutoInstall</option></term>
  976. <listitem>
  977. <para>
  978. Generate debug messages describing which packages are being
  979. automatically installed to resolve dependencies. This
  980. corresponds to the initial auto-install pass performed in,
  981. e.g., <literal>apt-get install</literal>, and not to the
  982. full <literal>apt</literal> dependency resolver; see
  983. <literal>Debug::pkgProblemResolver</literal> for that.
  984. </para>
  985. </listitem>
  986. </varlistentry>
  987. <varlistentry>
  988. <term><option>Debug::pkgDepCache::Marker</option></term>
  989. <listitem>
  990. <para>
  991. Generate debug messages describing which packages are marked
  992. as keep/install/remove while the ProblemResolver does his work.
  993. Each addition or deletion may trigger additional actions;
  994. they are shown indented two additional spaces under the original entry.
  995. The format for each line is <literal>MarkKeep</literal>,
  996. <literal>MarkDelete</literal> or <literal>MarkInstall</literal> followed by
  997. <literal>package-name &lt;a.b.c -&gt; d.e.f | x.y.z&gt; (section)</literal>
  998. where <literal>a.b.c</literal> is the current version of the package,
  999. <literal>d.e.f</literal> is the version considered for installation and
  1000. <literal>x.y.z</literal> is a newer version, but not considered for installation
  1001. (because of a low pin score). The later two can be omitted if there is none or if
  1002. it is the same as the installed version.
  1003. <literal>section</literal> is the name of the section the package appears in.
  1004. </para>
  1005. </listitem>
  1006. </varlistentry>
  1007. <varlistentry>
  1008. <term><option>Debug::pkgDPkgPM</option></term>
  1009. <listitem>
  1010. <para>
  1011. When invoking &dpkg;, output the precise command line with
  1012. which it is being invoked, with arguments separated by a
  1013. single space character.
  1014. </para>
  1015. </listitem>
  1016. </varlistentry>
  1017. <varlistentry>
  1018. <term><option>Debug::pkgDPkgProgressReporting</option></term>
  1019. <listitem>
  1020. <para>
  1021. Output all the data received from &dpkg; on the status file
  1022. descriptor and any errors encountered while parsing it.
  1023. </para>
  1024. </listitem>
  1025. </varlistentry>
  1026. <varlistentry>
  1027. <term><option>Debug::pkgOrderList</option></term>
  1028. <listitem>
  1029. <para>
  1030. Generate a trace of the algorithm that decides the order in
  1031. which <literal>apt</literal> should pass packages to
  1032. &dpkg;.
  1033. </para>
  1034. </listitem>
  1035. </varlistentry>
  1036. <varlistentry>
  1037. <term><option>Debug::pkgPackageManager</option></term>
  1038. <listitem>
  1039. <para>
  1040. Output status messages tracing the steps performed when
  1041. invoking &dpkg;.
  1042. </para>
  1043. </listitem>
  1044. </varlistentry>
  1045. <varlistentry>
  1046. <term><option>Debug::pkgPolicy</option></term>
  1047. <listitem>
  1048. <para>
  1049. Output the priority of each package list on startup.
  1050. </para>
  1051. </listitem>
  1052. </varlistentry>
  1053. <varlistentry>
  1054. <term><option>Debug::pkgProblemResolver</option></term>
  1055. <listitem>
  1056. <para>
  1057. Trace the execution of the dependency resolver (this
  1058. applies only to what happens when a complex dependency
  1059. problem is encountered).
  1060. </para>
  1061. </listitem>
  1062. </varlistentry>
  1063. <varlistentry>
  1064. <term><option>Debug::pkgProblemResolver::ShowScores</option></term>
  1065. <listitem>
  1066. <para>
  1067. Display a list of all installed packages with their calculated score
  1068. used by the pkgProblemResolver. The description of the package
  1069. is the same as described in <literal>Debug::pkgDepCache::Marker</literal>
  1070. </para>
  1071. </listitem>
  1072. </varlistentry>
  1073. <varlistentry>
  1074. <term><option>Debug::sourceList</option></term>
  1075. <listitem>
  1076. <para>
  1077. Print information about the vendors read from
  1078. <filename>/etc/apt/vendors.list</filename>.
  1079. </para>
  1080. </listitem>
  1081. </varlistentry>
  1082. <varlistentry>
  1083. <term><option>Debug::RunScripts</option></term>
  1084. <listitem>
  1085. <para>
  1086. Display the external commands that are called by apt hooks.
  1087. This includes e.g. the config options
  1088. <literal>DPkg::{Pre,Post}-Invoke</literal> or
  1089. <literal>APT::Update::{Pre,Post}-Invoke</literal>.
  1090. </para>
  1091. </listitem>
  1092. </varlistentry>
  1093. <!-- 2009/07/11 Currently used nowhere. The corresponding code
  1094. is commented.
  1095. <varlistentry>
  1096. <term><literal>Debug::Vendor</literal></term>
  1097. <listitem>
  1098. <para>
  1099. Print information about each vendor.
  1100. </para>
  1101. </listitem>
  1102. </varlistentry>
  1103. -->
  1104. </variablelist>
  1105. </refsect1>
  1106. <refsect1><title>Examples</title>
  1107. <para>&configureindex; is a
  1108. configuration file showing example values for all possible
  1109. options.</para>
  1110. </refsect1>
  1111. <refsect1><title>Files</title>
  1112. <variablelist>
  1113. &file-aptconf;
  1114. </variablelist>
  1115. </refsect1>
  1116. <refsect1><title>See Also</title>
  1117. <para>&apt-cache;, &apt-config;<!-- ? reading apt.conf -->, &apt-preferences;.</para>
  1118. </refsect1>
  1119. &manbugs;
  1120. </refentry>