is the command-line tool for handling packages, and may be considered the user's "back-end" to other tools using the APT library. Several "front-end" interfaces exist, such as dselect(8), aptitude, synaptic, gnome-apt and wajig.
Unless the
-h, or
--help
option is given, one of the commands below must be present.
update
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
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
dselect-upgrade
is used in conjunction with the traditional Debian packaging front-end,
dselect(8).
dselect-upgrade
follows the changes made by
dselect(8)
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
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. 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
install
is followed by one or more packages desired for installation. 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, unstable).
Both of the version selection mechanisms can downgrade packages and must be used with care.
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
remove
is identical to
install
except that packages are removed instead of installed. If a plus sign is appended to the package name (with no intervening space), the identified package will be installed instead of removed.
purge
purge
is identical to
remove
except that packages are removed and purged.
source
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. Source packages are tracked separately from binary packages via
deb-src
type lines in the
sources.list(5)
file. This probably will mean that you will not get the same source as the package you have installed or as you could install. If the --compile options is specified then the package will be compiled to a binary .deb using dpkg-buildpackage, 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
build-dep
causes apt-get to install/remove packages in an attempt to satisfy the build dependencies for a source package.
check
check
is a diagnostic tool; it updates the package cache and checks for broken dependencies.
clean
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(8)
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.
autoclean
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
autoremove
is used to remove packages that were automatically installed to satisfy dependencies for some package and that are no more needed.
OPTIONS
All command line options may be set using the configuration file, the descriptions indicate the configuration option to set. For boolean options you can override the config file by using something like
-f-,--no-f,
-f=no
or several other variations.
-d, --download-only
Download only; package files are only retrieved, not unpacked or installed. Configuration Item:
APT::Get::Download-Only.
-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. Any Package that are specified must 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(8)
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.
--no-download
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.
No action; perform a simulation of events that would occur but do not actually change the system. Configuration Item:
APT::Get::Simulate.
Simulate prints out a series of lines each one representing a dpkg operation, Configure (Conf), Remove (Remv), Unpack (Inst). Square brackets indicate broken packages with 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:
APT::Get::Assume-Yes.
-u, --show-upgraded
Show upgraded packages; Print out a list of all packages that are to be upgraded. Configuration Item:
APT::Get::Show-Upgraded.
-V, --verbose-versions
Show full versions for upgraded and installed packages. Configuration Item:
APT::Get::Show-Versions.
-b, --compile, --build
Compile source packages after downloading them. Configuration Item:
APT::Get::Compile.
--ignore-hold
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:
APT::Ignore-Hold.
--no-upgrade
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:
APT::Get::Upgrade.
--force-yes
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.
--print-uris
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.
--purge
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. Configuration Item:
APT::Get::Purge.
--reinstall
Re-Install packages that are already installed and at the newest version. Configuration Item:
APT::Get::ReInstall.
--list-cleanup
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:
APT::Get::List-Cleanup.
-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. The preferences file may further override this setting. 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*'
or
-t unstable. Configuration Item:
APT::Default-Release; see also the
apt_preferences(5)
manual page.
--trivial-only
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:
APT::Get::Trivial-Only.
--no-remove
If any packages are to be removed apt-get immediately aborts without prompting. Configuration Item:
APT::Get::Remove.
--auto-remove
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-source
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.
--arch-only
Only process architecture-dependent build-dependencies. Configuration Item:
APT::Get::Arch-Only.
--allow-unauthenticated
Ignore if packages can't be authenticated and don't prompt about it. This is usefull 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. See
apt.conf(5)
for syntax information.
-o, --option
Set a Configuration Option; This will set an arbitary configuration option. The syntax is
-o Foo::Bar=bar.
FILES
/etc/apt/sources.list
Locations to fetch packages from. Configuration Item:
Dir::Etc::SourceList.
Version preferences file. This is where you would specify "pinning", i.e. a preference to get certain packages from a separate source or from a different version of a distribution. Configuration Item:
Dir::Etc::Preferences.
/var/cache/apt/archives/
Storage area for retrieved package files. Configuration Item:
Dir::Cache::Archives.
/var/cache/apt/archives/partial/
Storage area for package files in transit. Configuration Item:
Dir::Cache::Archives
(implicit partial).
/var/lib/apt/lists/
Storage area for state information for each package resource specified in
sources.list(5)
Configuration Item:
Dir::State::Lists.
/var/lib/apt/lists/partial/
Storage area for state information in transit. Configuration Item:
Dir::State::Lists
(implicit partial).