doc/apt-get.8.xml

   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
   9 <refentry>
  10
  11  <refentryinfo>
  12    &apt-author.jgunthorpe;
  13    &apt-author.team;
  14    &apt-email;
  15    &apt-product;
  16    <!-- The last update date -->
  17    <date>2012-06-09T00:00:00Z</date>
  18  </refentryinfo>
  19
  20  <refmeta>
  21    <refentrytitle>apt-get</refentrytitle>
  22    <manvolnum>8</manvolnum>
  23    <refmiscinfo class="manual">APT</refmiscinfo>
  24  </refmeta>
  25
  26  <!-- Man page title -->
  27  <refnamediv>
  28     <refname>apt-get</refname>
  29     <refpurpose>APT package handling utility -- command-line interface</refpurpose>
  30  </refnamediv>
  31
  32  &synopsis-command-apt-get;
  33
  34  <refsect1><title>Description</title>
  35    <para><command>apt-get</command> is the command-line tool for handling packages, and may be
  36    considered the user's "back-end" to other tools using the APT
  37    library.  Several "front-end" interfaces exist, such as
  38    &aptitude;, &synaptic; and &wajig;.</para>
  39
  40    <para>Unless the <option>-h</option>, or <option>--help</option> option is given, one of the
  41    commands below must be present.</para>
  42
  43    <variablelist>
  44      <varlistentry><term><option>update</option></term>
  45      <listitem><para><literal>update</literal> is used to resynchronize the package index files from
  46      their sources. The indexes of available packages are fetched from the
  47      location(s) specified in <filename>/etc/apt/sources.list</filename>.
  48      For example, when using a Debian archive, this command retrieves and
  49      scans the <filename>Packages.gz</filename> files, so that information about new
  50      and updated packages is available. An <literal>update</literal> should always be
  51      performed before an <literal>upgrade</literal> or <literal>dist-upgrade</literal>. Please
  52      be aware that the overall progress meter will be incorrect as the size
  53      of the package files cannot be known in advance.</para></listitem>
  54      </varlistentry>
  55
  56      <varlistentry><term><option>upgrade</option></term>
  57      <listitem><para><literal>upgrade</literal> is used to install the newest versions of all packages
  58      currently installed on the system from the sources enumerated in
  59      <filename>/etc/apt/sources.list</filename>. Packages currently installed with
  60      new versions available are retrieved and upgraded; under no circumstances
  61      are currently installed packages removed, or packages not already installed
  62      retrieved and installed. New versions of currently installed packages that
  63      cannot be upgraded without changing the install status of another package
  64      will be left at their current version. An <literal>update</literal> must be
  65      performed first so that <command>apt-get</command> knows that new versions of packages are
  66      available.</para></listitem>
  67      </varlistentry>
  68
  69      <varlistentry><term><option>dist-upgrade</option></term>
  70      <listitem><para><literal>dist-upgrade</literal> in addition to performing the function of
  71      <literal>upgrade</literal>, also intelligently handles changing dependencies
  72      with new versions of packages; <command>apt-get</command> has a "smart" conflict
  73      resolution system, and it will attempt to upgrade the most important
  74      packages at the expense of less important ones if necessary.
  75      The <literal>dist-upgrade</literal> command may therefore remove some packages.
  76      The <filename>/etc/apt/sources.list</filename> file contains a list of locations
  77      from which to retrieve desired package files.
  78      See also &apt-preferences; for a mechanism for
  79      overriding the general settings for individual packages.</para></listitem>
  80      </varlistentry>
  81
  82      <varlistentry><term><option>dselect-upgrade</option></term>
  83      <listitem><para><literal>dselect-upgrade</literal>
  84      is used in conjunction with the traditional Debian packaging
  85      front-end, &dselect;. <literal>dselect-upgrade</literal>
  86      follows the changes made by &dselect; to the <literal>Status</literal>
  87      field of available packages, and performs the actions necessary to realize
  88      that state (for instance, the removal of old and the installation of new
  89      packages).</para></listitem>
  90      </varlistentry>
  91
  92      <varlistentry><term><option>install</option></term>
  93      <listitem>
  94          <para><literal>install</literal> is followed by one or more
  95          packages desired for installation or upgrading.
  96          Each package is a package name, not a fully qualified
  97          filename (for instance, in a Debian system,
  98          <package>apt-utils</package> would be the argument provided, not
  99          <filename>apt-utils_&apt-product-version;_amd64.deb</filename>). All packages required
 100          by the package(s) specified for installation will also
 101          be retrieved and installed.
 102          The <filename>/etc/apt/sources.list</filename> file is
 103          used to locate the desired packages. If a hyphen is
 104          appended to the package name (with no intervening space),
 105          the identified package will be removed if it is installed.
 106          Similarly a plus sign can be used to designate a
 107          package to install. These latter features may be used
 108          to override decisions made by apt-get's conflict
 109          resolution system.
 110          </para>
 111
 112      <para>A specific version of a package can be selected for installation by
 113      following the package name with an equals and the version of the package
 114      to select. This will cause that version to be located and selected for
 115      install. Alternatively a specific distribution can be selected by
 116      following the package name with a slash and the version of the
 117      distribution or the Archive name (stable, testing, unstable).</para>
 118
 119      <para>Both of the version selection mechanisms can downgrade packages and must
 120      be used with care.</para>
 121
 122         <para>This is also the target to use if you want to upgrade one or
 123                 more already-installed packages without upgrading every package
 124                 you have on your system. Unlike the "upgrade" target, which
 125                 installs the newest version of all currently installed packages,
 126                 "install" will install the newest version of only the package(s)
 127                 specified. Simply provide the name of the package(s) you wish
 128                 to upgrade, and if a newer version is available, it (and its
 129                 dependencies, as described above) will be downloaded and
 130                 installed.
 131         </para>
 132
 133      <para>Finally, the &apt-preferences; mechanism allows you to
 134      create an alternative installation policy for
 135      individual packages.</para>
 136
 137      <para>If no package matches the given expression and the expression contains one
 138      of '.', '?' or '*' then it is assumed to be a POSIX regular expression,
 139      and it is applied
 140      to all package names in the database. Any matches are then installed (or
 141      removed). Note that matching is done by substring so 'lo.*' matches 'how-lo'
 142      and 'lowest'. If this is undesired, anchor the regular expression
 143      with a '^' or '$' character, or create a more specific regular expression.</para></listitem>
 144      </varlistentry>
 145
 146      <varlistentry><term><option>remove</option></term>
 147      <listitem><para><literal>remove</literal> is identical to <literal>install</literal> except that packages are
 148          removed instead of installed. Note that removing a package leaves its
 149          configuration files on the system. If a plus sign is appended to the package
 150      name (with no intervening space), the identified package will be
 151      installed instead of removed.</para></listitem>
 152      </varlistentry>
 153
 154      <varlistentry><term><option>purge</option></term>
 155      <listitem><para><literal>purge</literal> is identical to <literal>remove</literal> except that packages are
 156      removed and purged (any configuration files are deleted too).</para></listitem>
 157      </varlistentry>
 158
 159      <varlistentry><term><option>source</option></term>
 160      <listitem><para><literal>source</literal> causes <command>apt-get</command> to fetch source packages. APT
 161      will examine the available packages to decide which source package to
 162      fetch. It will then find and download into the current directory the
 163      newest available version of that source package while respecting the
 164      default release, set with the option <literal>APT::Default-Release</literal>,
 165      the <option>-t</option> option or per package with the
 166      <literal>pkg/release</literal> syntax, if possible.</para>
 167
 168      <para>Source packages are tracked separately
 169      from binary packages via <literal>deb-src</literal> lines
 170      in the &sources-list; file. This means that you will need to add such a line
 171      for each repository you want to get sources from; otherwise you will probably
 172      get either the wrong (too old/too new) source versions or none at all.</para>
 173
 174      <para>If the <option>--compile</option> option is specified
 175      then the package will be compiled to a binary .deb using
 176      <command>dpkg-buildpackage</command> for the architecture as
 177      defined by the <command>--host-architecture</command> option.
 178      If <option>--download-only</option> is specified then the source package
 179      will not be unpacked.</para>
 180
 181      <para>A specific source version can be retrieved by postfixing the source name
 182      with an equals and then the version to fetch, similar to the mechanism
 183      used for the package files. This enables exact matching of the source
 184      package name and version, implicitly enabling the
 185      <literal>APT::Get::Only-Source</literal> option.</para>
 186
 187      <para>Note that source packages are not installed and tracked in the
 188      <command>dpkg</command> database like binary packages; they are simply downloaded
 189      to the current directory, like source tarballs.</para></listitem>
 190      </varlistentry>
 191
 192      <varlistentry><term><option>build-dep</option></term>
 193      <listitem><para><literal>build-dep</literal> causes apt-get to install/remove packages in an
 194      attempt to satisfy the build dependencies for a source package. By default the dependencies are
 195      satisfied to build the package natively. If desired a host-architecture can be specified
 196      with the <option>--host-architecture</option> option instead.</para></listitem>
 197      </varlistentry>
 198
 199      <varlistentry><term><option>check</option></term>
 200      <listitem><para><literal>check</literal> is a diagnostic tool; it updates the package cache and checks
 201      for broken dependencies.</para></listitem>
 202      </varlistentry>
 203
 204      <varlistentry><term><option>download</option></term>
 205        <listitem><para><literal>download</literal> will download the given
 206            binary package into the current directory.
 207        </para></listitem>
 208      </varlistentry>
 209
 210      <varlistentry><term><option>clean</option></term>
 211      <listitem><para><literal>clean</literal> clears out the local repository of retrieved package
 212      files. It removes everything but the lock file from
 213      <filename>&cachedir;/archives/</filename> and
 214      <filename>&cachedir;/archives/partial/</filename>.</para></listitem>
 215      </varlistentry>
 216
 217      <varlistentry><term><option>autoclean</option> (and the <option>auto-clean</option> alias since 1.1)</term>
 218      <listitem><para>Like <literal>clean</literal>, <literal>autoclean</literal> clears out the local
 219      repository of retrieved package files. The difference is that it only
 220      removes package files that can no longer be downloaded, and are largely
 221      useless. This allows a cache to be maintained over a long period without
 222      it growing out of control. The configuration option
 223      <literal>APT::Clean-Installed</literal> will prevent installed packages from being
 224      erased if it is set to off.</para></listitem>
 225      </varlistentry>
 226
 227      <varlistentry><term><option>autoremove</option> (and the <option>auto-remove</option> alias since 1.1)</term>
 228      <listitem><para><literal>autoremove</literal> is used to remove packages that were automatically
 229      installed to satisfy dependencies for other packages and are now no longer needed.</para></listitem>
 230      </varlistentry>
 231
 232      <varlistentry><term><option>changelog</option></term>
 233         <listitem><para><literal>changelog</literal> tries to download the
 234               changelog of a package and displays it through
 235               <command>sensible-pager</command>.  By default it
 236               displays the changelog for the version that is installed.
 237               However, you can specify the same options as for the
 238               <option>install</option> command.</para>
 239        </listitem>
 240      </varlistentry>
 241
 242      <varlistentry><term><option>indextargets</option></term>
 243         <listitem><para>Displays by default a deb822 formatted listing of
 244               information about all data files (aka index targets) <command>apt-get
 245                  update</command> would download. Supports a
 246               <option>--format</option> option to modify the output format as
 247               well as accepts lines of the default output to filter the records
 248               by. The command is mainly used as an interface for external tools
 249               working with APT to get information as well as filenames for
 250               downloaded files so they can use them as well instead of
 251               downloading them again on their own. Detailed documentation is
 252               omitted here and can instead be found in the source tree in
 253               <literal><filename>doc/acquire-additional-files.txt</filename></literal>.
 254            </para>
 255         </listitem>
 256      </varlistentry>
 257
 258
 259    </variablelist>
 260  </refsect1>
 261
 262  <refsect1><title>options</title>
 263    &apt-cmdblurb;
 264
 265    <variablelist>
 266      <varlistentry><term><option>--no-install-recommends</option></term>
 267      <listitem><para>Do not consider recommended packages as a dependency for installing.
 268      Configuration Item: <literal>APT::Install-Recommends</literal>.</para></listitem>
 269      </varlistentry>
 270
 271      <varlistentry><term><option>--install-suggests</option></term>
 272      <listitem><para>Consider suggested packages as a dependency for installing.
 273      Configuration Item: <literal>APT::Install-Suggests</literal>.</para></listitem>
 274      </varlistentry>
 275
 276      <varlistentry><term><option>-d</option></term><term><option>--download-only</option></term>
 277      <listitem><para>Download only; package files are only retrieved, not unpacked or installed.
 278      Configuration Item: <literal>APT::Get::Download-Only</literal>.</para></listitem>
 279      </varlistentry>
 280
 281      <varlistentry><term><option>-f</option></term><term><option>--fix-broken</option></term>
 282      <listitem><para>Fix; attempt to correct a system with broken dependencies in
 283      place. This option, when used with install/remove, can omit any packages
 284      to permit APT to deduce a likely solution. If packages are specified,
 285      these have to completely correct the problem. The option is sometimes necessary when
 286      running APT for the first time; APT itself does not allow broken package
 287      dependencies to exist on a system. It is possible that a system's
 288      dependency structure can be so corrupt as to require manual intervention
 289      (which usually means using <command>dpkg --remove</command> to eliminate some of
 290      the offending packages). Use of this option together with <option>-m</option> may produce an
 291      error in some situations.
 292      Configuration Item: <literal>APT::Get::Fix-Broken</literal>.</para></listitem>
 293      </varlistentry>
 294
 295      <varlistentry><term><option>-m</option></term><term><option>--ignore-missing</option></term>
 296      <term><option>--fix-missing</option></term>
 297      <listitem><para>Ignore missing packages; if packages cannot be retrieved or fail the
 298      integrity check after retrieval (corrupted package files), hold back
 299      those packages and handle the result. Use of this option together with
 300      <option>-f</option> may produce an error in some situations. If a package is
 301      selected for installation (particularly if it is mentioned on the
 302      command line) and it could not be downloaded then it will be silently
 303      held back.
 304      Configuration Item: <literal>APT::Get::Fix-Missing</literal>.</para></listitem>
 305      </varlistentry>
 306
 307      <varlistentry><term><option>--no-download</option></term>
 308      <listitem><para>Disables downloading of packages. This is best used with
 309      <option>--ignore-missing</option> to force APT to use only the .debs it has
 310      already downloaded.
 311      Configuration Item: <literal>APT::Get::Download</literal>.</para></listitem>
 312      </varlistentry>
 313
 314      <varlistentry><term><option>-q</option></term><term><option>--quiet</option></term>
 315      <listitem><para>Quiet; produces output suitable for logging, omitting progress indicators.
 316      More q's will produce more quiet up to a maximum of 2. You can also use
 317      <option>-q=#</option> to set the quiet level, overriding the configuration file.
 318      Note that quiet level 2 implies <option>-y</option>; you should never use -qq
 319      without a no-action modifier such as -d, --print-uris or -s as APT may
 320      decide to do something you did not expect.
 321      Configuration Item: <literal>quiet</literal>.</para></listitem>
 322      </varlistentry>
 323
 324      <varlistentry><term><option>-s</option></term>
 325                    <term><option>--simulate</option></term>
 326                    <term><option>--just-print</option></term>
 327                    <term><option>--dry-run</option></term>
 328                    <term><option>--recon</option></term>
 329                    <term><option>--no-act</option></term>
 330      <listitem><para>No action; perform a simulation of events that would occur
 331            based on the current system state but do not actually change the
 332            system. Locking will be disabled (<option>Debug::NoLocking</option>)
 333            so the system state could change while <command>apt-get</command> is
 334            running. Simulations can also be executed by non-root users which might
 335            not have read access to all apt configuration distorting the simulation.
 336            A notice expressing this warning is also shown by default for non-root
 337            users (<option>APT::Get::Show-User-Simulation-Note</option>).
 338            Configuration Item: <literal>APT::Get::Simulate</literal>.</para>
 339
 340      <para>Simulated runs print out a series of lines, each representing a <command>dpkg</command>
 341      operation: configure (<literal>Conf</literal>), remove (<literal>Remv</literal>)
 342      or unpack (<literal>Inst</literal>). Square brackets indicate broken packages, and
 343      empty square brackets indicate breaks that are of no consequence (rare).</para></listitem>
 344      </varlistentry>
 345
 346      <varlistentry><term><option>-y</option></term><term><option>--yes</option></term>
 347                    <term><option>--assume-yes</option></term>
 348      <listitem><para>Automatic yes to prompts; assume "yes" as answer to all prompts and run
 349      non-interactively. If an undesirable situation, such as changing a held
 350      package, trying to install a unauthenticated package or removing an essential package
 351      occurs then <literal>apt-get</literal> will abort.
 352      Configuration Item: <literal>APT::Get::Assume-Yes</literal>.</para></listitem>
 353      </varlistentry>
 354
 355      <varlistentry><term><option>--assume-no</option></term>
 356      <listitem><para>Automatic "no" to all prompts.
 357      Configuration Item: <literal>APT::Get::Assume-No</literal>.</para></listitem>
 358      </varlistentry>
 359
 360      <varlistentry><term><option>-u</option></term><term><option>--show-upgraded</option></term>
 361      <listitem><para>Show upgraded packages; print out a list of all packages that are to be
 362      upgraded.
 363      Configuration Item: <literal>APT::Get::Show-Upgraded</literal>.</para></listitem>
 364      </varlistentry>
 365
 366      <varlistentry><term><option>-V</option></term><term><option>--verbose-versions</option></term>
 367      <listitem><para>Show full versions for upgraded and installed packages.
 368      Configuration Item: <literal>APT::Get::Show-Versions</literal>.</para></listitem>
 369      </varlistentry>
 370
 371      <varlistentry><term><option>-a</option></term>
 372                    <term><option>--host-architecture</option></term>
 373      <listitem><para>This option controls the architecture packages are built for
 374      by <command>apt-get source --compile</command> and how cross-builddependencies
 375      are satisfied. By default is it not set which means that the host architecture
 376      is the same as the build architecture (which is defined by <literal>APT::Architecture</literal>).
 377      Configuration Item: <literal>APT::Get::Host-Architecture</literal>.
 378      </para></listitem>
 379      </varlistentry>
 380
 381      <varlistentry><term><option>-P</option></term>
 382                    <term><option>--build-profiles</option></term>
 383      <listitem><para>This option controls the activated build profiles for which
 384      a source package is built by <command>apt-get source --compile</command> and
 385      how build dependencies are satisfied. By default no build profile is active.
 386      More than one build profile can be activated at a time by concatenating them
 387      with a comma.
 388      Configuration Item: <literal>APT::Build-Profiles</literal>.
 389      </para></listitem>
 390      </varlistentry>
 391
 392      <varlistentry><term><option>-b</option></term><term><option>--compile</option></term>
 393                    <term><option>--build</option></term>
 394      <listitem><para>Compile source packages after downloading them.
 395      Configuration Item: <literal>APT::Get::Compile</literal>.</para></listitem>
 396      </varlistentry>
 397
 398      <varlistentry><term><option>--ignore-hold</option></term>
 399      <listitem><para>Ignore package holds; this causes <command>apt-get</command> to ignore a hold
 400      placed on a package. This may be useful in conjunction with
 401      <literal>dist-upgrade</literal> to override a large number of undesired holds.
 402      Configuration Item: <literal>APT::Ignore-Hold</literal>.</para></listitem>
 403      </varlistentry>
 404
 405      <varlistentry><term><option>--with-new-pkgs</option></term>
 406      <listitem><para>Allow installing new packages when used in
 407      conjunction with <literal>upgrade</literal>.  This is useful if
 408      the update of a installed package requires new dependencies to be
 409      installed. Instead of holding the package back <literal>upgrade</literal>
 410      will upgrade the package and install the new dependencies. Note that
 411      <literal>upgrade</literal> with this option will never remove packages,
 412      only allow adding new ones.
 413      Configuration Item:  <literal>APT::Get::Upgrade-Allow-New</literal>.
 414      </para></listitem>
 415      </varlistentry>
 416
 417      <varlistentry><term><option>--no-upgrade</option></term>
 418      <listitem><para>Do not upgrade packages; when used in conjunction with <literal>install</literal>,
 419      <literal>no-upgrade</literal> will prevent packages on the command line
 420      from being upgraded if they are already installed.
 421      Configuration Item: <literal>APT::Get::Upgrade</literal>.</para></listitem>
 422      </varlistentry>
 423
 424      <varlistentry><term><option>--only-upgrade</option></term>
 425      <listitem><para>Do not install new packages; when used in conjunction
 426      with <literal>install</literal>, <literal>only-upgrade</literal> will
 427      install upgrades for already installed packages only and ignore requests
 428      to install new packages.
 429      Configuration Item: <literal>APT::Get::Only-Upgrade</literal>.</para></listitem>
 430      </varlistentry>
 431
 432      <varlistentry><term><option>--allow-downgrades</option></term>
 433      <listitem><para>This is a dangerous option that will cause apt to continue
 434      without prompting if it is doing downgrades. It
 435      should not be used except in very special situations. Using
 436      it can potentially destroy your system!
 437      Configuration Item: <literal>APT::Get::allow-downgrades</literal>. Introduced in APT 1.1.</para></listitem>
 438      </varlistentry>
 439
 440      <varlistentry><term><option>--allow-remove-essential</option></term>
 441      <listitem><para>Force yes; this is a dangerous option that will cause apt to continue
 442      without prompting if it is removing essentials. It
 443      should not be used except in very special situations. Using
 444      it can potentially destroy your system!
 445      Configuration Item: <literal>APT::Get::allow-remove-essential</literal>. Introduced in APT 1.1.</para></listitem>
 446      </varlistentry>
 447
 448      <varlistentry><term><option>--allow-change-held-packages</option></term>
 449      <listitem><para>Force yes; this is a dangerous option that will cause apt to continue
 450      without prompting if it is changing held packages. It
 451      should not be used except in very special situations. Using
 452      it can potentially destroy your system!
 453      Configuration Item: <literal>APT::Get::allow-change-held-packages</literal>. Introduced in APT 1.1.</para></listitem>
 454      </varlistentry>
 455
 456      <varlistentry><term><option>--force-yes</option></term>
 457      <listitem><para>Force yes; this is a dangerous option that will cause apt to continue
 458      without prompting if it is doing something potentially harmful. It
 459      should not be used except in very special situations. Using
 460      <literal>force-yes</literal> can potentially destroy your system!
 461      Configuration Item: <literal>APT::Get::force-yes</literal>. This is deprecated and replaced by <option>--allow-downgrades</option>, <option>--allow-remove-essential</option>, <option>--allow-change-held-packages</option> in 1.1. </para></listitem>
 462      </varlistentry>
 463
 464      <varlistentry><term><option>--print-uris</option></term>
 465      <listitem><para>Instead of fetching the files to install their URIs are printed. Each
 466      URI will have the path, the destination file name, the size and the expected
 467      MD5 hash. Note that the file name to write to will not always match
 468      the file name on the remote site! This also works with the
 469      <literal>source</literal> and <literal>update</literal> commands. When used with the
 470      <literal>update</literal> command the MD5 and size are not included, and it is
 471      up to the user to decompress any compressed files.
 472      Configuration Item: <literal>APT::Get::Print-URIs</literal>.</para></listitem>
 473      </varlistentry>
 474
 475      <varlistentry><term><option>--purge</option></term>
 476      <listitem><para>Use purge instead of remove for anything that would be removed.
 477      An asterisk ("*") will be displayed next to packages which are
 478          scheduled to be purged. <option>remove --purge</option> is equivalent to the
 479          <option>purge</option> command.
 480      Configuration Item: <literal>APT::Get::Purge</literal>.</para></listitem>
 481      </varlistentry>
 482
 483      <varlistentry><term><option>--reinstall</option></term>
 484      <listitem><para>Re-install packages that are already installed and at the newest version.
 485      Configuration Item: <literal>APT::Get::ReInstall</literal>.</para></listitem>
 486      </varlistentry>
 487
 488      <varlistentry><term><option>--list-cleanup</option></term>
 489      <listitem><para>This option is on by default; use <literal>--no-list-cleanup</literal> to turn
 490      it off. When it is on, <command>apt-get</command> will automatically manage the contents
 491      of <filename>&statedir;/lists</filename> to ensure that obsolete files are erased.
 492      The only reason to turn it off is if you frequently change your sources list.
 493      Configuration Item: <literal>APT::Get::List-Cleanup</literal>.</para></listitem>
 494      </varlistentry>
 495
 496      <varlistentry><term><option>-t</option></term>
 497                    <term><option>--target-release</option></term>
 498                    <term><option>--default-release</option></term>
 499      <listitem><para>This option controls the default input to the policy engine; it creates
 500      a default pin at priority 990 using the specified release string.
 501      This overrides the general settings in <filename>/etc/apt/preferences</filename>.
 502      Specifically pinned packages are not affected by the value
 503      of this option. In short, this option
 504      lets you have simple control over which distribution packages will be
 505      retrieved from. Some common examples might be
 506      <option>-t '2.1*'</option>, <option>-t unstable</option>
 507      or <option>-t sid</option>.
 508      Configuration Item: <literal>APT::Default-Release</literal>;
 509      see also the &apt-preferences; manual page.</para></listitem>
 510      </varlistentry>
 511
 512      <varlistentry><term><option>--trivial-only</option></term>
 513      <listitem><para>
 514      Only perform operations that are 'trivial'. Logically this can be considered
 515      related to <option>--assume-yes</option>; where <option>--assume-yes</option> will answer
 516      yes to any prompt, <option>--trivial-only</option> will answer no.
 517      Configuration Item: <literal>APT::Get::Trivial-Only</literal>.</para></listitem>
 518      </varlistentry>
 519
 520      <varlistentry><term><option>--no-remove</option></term>
 521      <listitem><para>If any packages are to be removed apt-get immediately aborts without
 522      prompting.
 523      Configuration Item: <literal>APT::Get::Remove</literal>.</para></listitem>
 524      </varlistentry>
 525
 526      <varlistentry><term><option>--auto-remove</option></term>
 527      <listitem><para>If the command is either <literal>install</literal> or <literal>remove</literal>,
 528      then this option acts like running the <literal>autoremove</literal> command, removing unused
 529      dependency packages. Configuration Item: <literal>APT::Get::AutomaticRemove</literal>.
 530      </para></listitem>
 531      </varlistentry>
 532
 533      <varlistentry><term><option>--only-source</option></term>
 534      <listitem><para>Only has meaning for the
 535      <literal>source</literal> and <literal>build-dep</literal>
 536      commands.  Indicates that the given source names are not to be
 537      mapped through the binary table.  This means that if this option
 538      is specified, these commands will only accept source package
 539      names as arguments, rather than accepting binary package names
 540      and looking up the corresponding source package.  Configuration
 541      Item: <literal>APT::Get::Only-Source</literal>.</para></listitem>
 542      </varlistentry>
 543
 544      <varlistentry><term><option>--diff-only</option></term><term><option>--dsc-only</option></term><term><option>--tar-only</option></term>
 545      <listitem><para>Download only the diff, dsc, or tar file of a source archive.
 546      Configuration Item: <literal>APT::Get::Diff-Only</literal>, <literal>APT::Get::Dsc-Only</literal>, and
 547      <literal>APT::Get::Tar-Only</literal>.</para></listitem>
 548      </varlistentry>
 549
 550      <varlistentry><term><option>--arch-only</option></term>
 551      <listitem><para>Only process architecture-dependent build-dependencies.
 552      Configuration Item: <literal>APT::Get::Arch-Only</literal>.</para></listitem>
 553      </varlistentry>
 554
 555      <varlistentry><term><option>--allow-unauthenticated</option></term>
 556      <listitem><para>Ignore if packages can't be authenticated and don't prompt
 557            about it.  This can be useful while working with local repositories,
 558            but is a huge security risk if data authenticity isn't ensured in
 559            another way by the user itself.  The usage of the
 560            <option>Trusted</option> option for &sources-list; entries should
 561            usually be preferred over this global override.  Configuration Item:
 562            <literal>APT::Get::AllowUnauthenticated</literal>.</para></listitem>
 563      </varlistentry>
 564
 565      <varlistentry><term><option>--no-allow-insecure-repositories</option></term>
 566      <listitem><para>Forbid the update command to acquire unverifiable
 567      data from configured sources. Apt will fail at the update command
 568      for repositories without valid cryptographically signatures.
 569
 570      Configuration Item: <literal>Acquire::AllowInsecureRepositories</literal>.</para></listitem>
 571      </varlistentry>
 572
 573      <varlistentry><term><option>--show-progress</option></term>
 574      <listitem><para>Show user friendly progress information in the
 575      terminal window when packages are installed, upgraded or
 576      removed. For a machine parsable version of this data see
 577      README.progress-reporting in the apt doc directory.
 578      Configuration Item: <literal>Dpkg::Progress</literal> and <literal>Dpkg::Progress-Fancy</literal>.</para></listitem>
 579      </varlistentry>
 580
 581
 582      &apt-commonoptions;
 583
 584    </variablelist>
 585  </refsect1>
 586
 587  <refsect1><title>Files</title>
 588    <variablelist>
 589      &file-sourceslist;
 590      &file-aptconf;
 591      &file-preferences;
 592      &file-cachearchives;
 593      &file-statelists;
 594    </variablelist>
 595  </refsect1>
 596
 597  <refsect1><title>See Also</title>
 598    <para>&apt-cache;, &apt-cdrom;, &dpkg;, &sources-list;,
 599    &apt-conf;, &apt-config;, &apt-secure;,
 600    The APT User's guide in &guidesdir;, &apt-preferences;, the APT Howto.</para>
 601  </refsect1>
 602
 603  <refsect1><title>Diagnostics</title>
 604    <para><command>apt-get</command> returns zero on normal operation, decimal 100 on error.</para>
 605  </refsect1>
 606  &manbugs;
 607 </refentry>