apt-get(8) - APT package handling utility - - command-line interface
apt-get [-sqdyfmubV] [-o= config_string ] [-c= config_file ] [-t= target_release]
        [-a= default_architecture] {update | upgrade | dselect-upgrade | dist-upgrade |
        install pkg [ { =pkg_version_number | /target_release } ] ...  | remove pkg...  | purge pkg...  |
        source pkg [ { =pkg_version_number | /target_release } ] ...  | build-dep pkg...  | check | clean
        | autoclean | autoremove | {-v | --version} | {-h | --help}}
    update is used to resynchronize the package index files from their sources. The indexes of available
    packages are fetched from the location(s) specified in /etc/apt/sources.list. For example, when using
    a Debian archive, this command retrieves and scans the Packages.gz files, so that information about
    new and updated packages is available. An update should always be performed before an upgrade or
    dist-upgrade. Please be aware that the overall progress meter will be incorrect as the size of the
    package files cannot be known in advance.
    upgrade is used to install the newest versions of all packages currently installed on the system from
    the sources enumerated in /etc/apt/sources.list. Packages currently installed with new versions
    available are retrieved and upgraded; under no circumstances are currently installed packages
    removed, or packages not already installed retrieved and installed. New versions of currently
    installed packages that cannot be upgraded without changing the install status of another package
    will be left at their current version. An update must be performed first so that apt-get knows that
    new versions of packages are available.
    dselect-upgrade is used in conjunction with the traditional Debian packaging front-end, dselect(1).
    dselect-upgrade follows the changes made by dselect(1) to the Status field of available packages, and
    performs the actions necessary to realize that state (for instance, the removal of old and the
    installation of new packages).
    dist-upgrade in addition to performing the function of upgrade, also intelligently handles changing
    dependencies with new versions of packages; apt-get has a "smart" conflict resolution system, and it
    will attempt to upgrade the most important packages at the expense of less important ones if
    necessary. So, dist-upgrade command may remove some packages. The /etc/apt/sources.list file contains
    a list of locations from which to retrieve desired package files. See also apt_preferences(5) for a
    mechanism for overriding the general settings for individual packages.
    install is followed by one or more packages desired for installation or upgrading. Each package is a
    package name, not a fully qualified filename (for instance, in a Debian GNU/Linux system, libc6 would
    be the argument provided, not libc6_1.9.6-2.deb). All packages required by the package(s) specified
    for installation will also be retrieved and installed. The /etc/apt/sources.list file is used to
    locate the desired packages. If a hyphen is appended to the package name (with no intervening space),
    the identified package will be removed if it is installed. Similarly a plus sign can be used to
    designate a package to install. These latter features may be used to override decisions made by
    apt-get's conflict resolution system.

    A specific version of a package can be selected for installation by following the package name with
    an equals and the version of the package to select. This will cause that version to be located and
    selected for install. Alternatively a specific distribution can be selected by following the package
    name with a slash and the version of the distribution or the Archive name (stable, testing,

    Both of the version selection mechanisms can downgrade packages and must be used with care.

    This is also the target to use if you want to upgrade one or more already-installed packages without
    upgrading every package you have on your system. Unlike the "upgrade" target, which installs the
    newest version of all currently installed packages, "install" will install the newest version of only
    the package(s) specified. Simply provide the name of the package(s) you wish to upgrade, and if a
    newer version is available, it (and its dependencies, as described above) will be downloaded and

    Finally, the apt_preferences(5) mechanism allows you to create an alternative installation policy for
    individual packages.

    If no package matches the given expression and the expression contains one of '.', '?' or '*' then it
    is assumed to be a POSIX regular expression, and it is applied to all package names in the database.
    Any matches are then installed (or removed). Note that matching is done by substring so 'lo.*'
    matches 'how-lo' and 'lowest'. If this is undesired, anchor the regular expression with a '^' or '$'
    character, or create a more specific regular expression.
    remove is identical to install except that packages are removed instead of installed. Note the
    removing a package leaves its configuration files in system. If a plus sign is appended to the
    package name (with no intervening space), the identified package will be installed instead of
    purge is identical to remove except that packages are removed and purged (any configuration files are
    deleted too).
    source causes apt-get to fetch source packages. APT will examine the available packages to decide
    which source package to fetch. It will then find and download into the current directory the newest
    available version of that source package while respect the default release, set with the option
    APT::Default-Release, the -t option or per package with the pkg/release syntax, if possible.

    Source packages are tracked separately from binary packages via deb-src type lines in the
    sources.list(5) file. This means that you will need to add such a line for each repository you want
    to get sources from. If you don't do this you will properly get another (newer, older or none) source
    version than the one you have installed or could install.

    If the --compile option is specified then the package will be compiled to a binary .deb using
    dpkg-buildpackage for the architecture as defined by the --host-architecture option. If
    --download-only is specified then the source package will not be unpacked.

    A specific source version can be retrieved by postfixing the source name with an equals and then the
    version to fetch, similar to the mechanism used for the package files. This enables exact matching of
    the source package name and version, implicitly enabling the APT::Get::Only-Source option.

    Note that source packages are not tracked like binary packages, they exist only in the current
    directory and are similar to downloading source tar balls.
    build-dep causes apt-get to install/remove packages in an attempt to satisfy the build dependencies
    for a source package. By default the dependencies are satisfied to build the package natively. If
    desired a host-architecture can be specified with the --host-architecture option instead.
    check is a diagnostic tool; it updates the package cache and checks for broken dependencies.
    download will download the given binary package into the current directory.
    clean clears out the local repository of retrieved package files. It removes everything but the lock
    file from /var/cache/apt/archives/ and /var/cache/apt/archives/partial/. When APT is used as a
    dselect(1) method, clean is run automatically. Those who do not use dselect will likely want to run
    apt-get clean from time to time to free up disk space.
    Like clean, autoclean clears out the local repository of retrieved package files. The difference is
    that it only removes package files that can no longer be downloaded, and are largely useless. This
    allows a cache to be maintained over a long period without it growing out of control. The
    configuration option APT::Clean-Installed will prevent installed packages from being erased if it is
    set to off.
    autoremove is used to remove packages that were automatically installed to satisfy dependencies for
    other packages and are now no longer needed.
    changelog downloads a package changelog and displays it through sensible-pager. The server name and
    base directory is defined in the APT::Changelogs::Server variable (e. g.
    http://packages.debian.org/changelogs for Debian or http://changelogs.ubuntu.com/changelogs for
    Ubuntu). By default it displays the changelog for the version that is installed. However, you can
    specify the same options as for the install command.
    Do not consider recommended packages as a dependency for installing. Configuration Item:
    Consider suggested packages as a dependency for installing. Configuration Item:
-d, --download-only
    Download only; package files are only retrieved, not unpacked or installed. Configuration Item:
-f, --fix-broken
    Fix; attempt to correct a system with broken dependencies in place. This option, when used with
    install/remove, can omit any packages to permit APT to deduce a likely solution. If packages are
    specified, these have to completely correct the problem. The option is sometimes necessary when
    running APT for the first time; APT itself does not allow broken package dependencies to exist on a
    system. It is possible that a system's dependency structure can be so corrupt as to require manual
    intervention (which usually means using dselect(1) or dpkg --remove to eliminate some of the
    offending packages). Use of this option together with -m may produce an error in some situations.
    Configuration Item: APT::Get::Fix-Broken.
-m, --ignore-missing, --fix-missing
    Ignore missing packages; If packages cannot be retrieved or fail the integrity check after retrieval
    (corrupted package files), hold back those packages and handle the result. Use of this option
    together with -f may produce an error in some situations. If a package is selected for installation
    (particularly if it is mentioned on the command line) and it could not be downloaded then it will be
    silently held back. Configuration Item: APT::Get::Fix-Missing.
    Disables downloading of packages. This is best used with --ignore-missing to force APT to use only
    the .debs it has already downloaded. Configuration Item: APT::Get::Download.
-q, --quiet
    Quiet; produces output suitable for logging, omitting progress indicators. More q's will produce more
    quiet up to a maximum of 2. You can also use -q=# to set the quiet level, overriding the
    configuration file. Note that quiet level 2 implies -y, you should never use -qq without a no-action
    modifier such as -d, --print-uris or -s as APT may decided to do something you did not expect.
    Configuration Item: quiet.
-s, --simulate, --just-print, --dry-run, --recon, --no-act
    No action; perform a simulation of events that would occur but do not actually change the system.
    Configuration Item: APT::Get::Simulate.

    Simulation run as user will deactivate locking (Debug::NoLocking) automatic. Also a notice will be
    displayed indicating that this is only a simulation, if the option
    APT::Get::Show-User-Simulation-Note is set (Default: true). Neither NoLocking nor the notice will be
    triggered if run as root (root should know what he is doing without further warnings by apt-get).

    Simulate prints out a series of lines each one representing a dpkg operation, Configure (Conf),
    Remove (Remv), Unpack (Inst). Square brackets indicate broken packages and empty set of square
    brackets meaning breaks that are of no consequence (rare).
-y, --yes, --assume-yes
    Automatic yes to prompts; assume "yes" as answer to all prompts and run non-interactively. If an
    undesirable situation, such as changing a held package, trying to install a unauthenticated package
    or removing an essential package occurs then apt-get will abort. Configuration Item:
    Automatic "no" to all prompts. Configuration Item: APT::Get::Assume-No.
-u, --show-upgraded
    Show upgraded packages; Print out a list of all packages that are to be upgraded. Configuration Item:
-V, --verbose-versions
    Show full versions for upgraded and installed packages. Configuration Item: APT::Get::Show-Versions.
-a, --host-architecture
    This option controls the architecture packages are built for by apt-get source --compile and how
    cross-builddependencies are satisfied. By default is it not set which means that the host
    architecture is the same as the build architecture (which is defined by APT::Architecture).
    Configuration Item: APT::Get::Host-Architecture
-b, --compile, --build
    Compile source packages after downloading them. Configuration Item: APT::Get::Compile.
    Ignore package Holds; This causes apt-get to ignore a hold placed on a package. This may be useful in
    conjunction with dist-upgrade to override a large number of undesired holds. Configuration Item:
    Do not upgrade packages; When used in conjunction with install, no-upgrade will prevent packages on
    the command line from being upgraded if they are already installed. Configuration Item:
    Do not install new packages; When used in conjunction with install, only-upgrade will prevent
    packages on the command line from being upgraded if they are not already installed. Configuration
    Item: APT::Get::Only-Upgrade.
    Force yes; This is a dangerous option that will cause apt to continue without prompting if it is
    doing something potentially harmful. It should not be used except in very special situations. Using
    force-yes can potentially destroy your system! Configuration Item: APT::Get::force-yes.
    Instead of fetching the files to install their URIs are printed. Each URI will have the path, the
    destination file name, the size and the expected md5 hash. Note that the file name to write to will
    not always match the file name on the remote site! This also works with the source and update
    commands. When used with the update command the MD5 and size are not included, and it is up to the
    user to decompress any compressed files. Configuration Item: APT::Get::Print-URIs.
    Use purge instead of remove for anything that would be removed. An asterisk ("*") will be displayed
    next to packages which are scheduled to be purged.  remove --purge is equivalent to the purge
    command. Configuration Item: APT::Get::Purge.
    Re-Install packages that are already installed and at the newest version. Configuration Item:
    This option defaults to on, use --no-list-cleanup to turn it off. When on apt-get will automatically
    manage the contents of /var/lib/apt/lists to ensure that obsolete files are erased. The only reason
    to turn it off is if you frequently change your source list. Configuration Item:
-t, --target-release, --default-release
    This option controls the default input to the policy engine, it creates a default pin at priority 990
    using the specified release string. This overrides the general settings in /etc/apt/preferences.
    Specifically pinned packages are not affected by the value of this option. In short, this option lets
    you have simple control over which distribution packages will be retrieved from. Some common examples
    might be -t '2.1*', -t unstable or -t sid. Configuration Item: APT::Default-Release; see also the
    apt_preferences(5) manual page.
    Only perform operations that are 'trivial'. Logically this can be considered related to --assume-yes,
    where --assume-yes will answer yes to any prompt, --trivial-only will answer no. Configuration Item:
    If any packages are to be removed apt-get immediately aborts without prompting. Configuration Item:
    If the command is either install or remove, then this option acts like running autoremove command,
    removing the unused dependency packages. Configuration Item: APT::Get::AutomaticRemove.
    Only has meaning for the source and build-dep commands. Indicates that the given source names are not
    to be mapped through the binary table. This means that if this option is specified, these commands
    will only accept source package names as arguments, rather than accepting binary package names and
    looking up the corresponding source package. Configuration Item: APT::Get::Only-Source.
--diff-only, --dsc-only, --tar-only
    Download only the diff, dsc, or tar file of a source archive. Configuration Item:
    APT::Get::Diff-Only, APT::Get::Dsc-Only, and APT::Get::Tar-Only.
    Only process architecture-dependent build-dependencies. Configuration Item: APT::Get::Arch-Only.
    Ignore if packages can't be authenticated and don't prompt about it. This is useful for tools like
    pbuilder. Configuration Item: APT::Get::AllowUnauthenticated.
-h, --help
    Show a short usage summary.
-v, --version
    Show the program version.
-c, --config-file
    Configuration File; Specify a configuration file to use. The program will read the default
    configuration file and then this configuration file. If configuration settings need to be set before
    the default configuration files are parsed specify a file with the APT_CONFIG environment variable.
    See apt.conf(5) for syntax information.
-o, --option
    Set a Configuration Option; This will set an arbitrary configuration option. The syntax is -o
    Foo::Bar=bar.  -o and --option can be used multiple times to set different options.