apt-get is the command-line tool for handling packages, and may be
considered the user's "back-end" to other tools using the APT library.
Unless the -h, or --help option is given one of the
commands below must be present.
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
is used in conjunction with the traditional Debian GNU/Linux 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
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.
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 em(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, frozen, unstable).
Both of the version selection mechanisms can downgrade packages and must
be used with care.
If no package matches the given expression and the expression contains one
of '.', '?' or '*' then it is assumed to be a POSIX regex 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 prefix with a '^' character.
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
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
Note that source packages are not tracked like binary packages, they
exist only in the current directory and are similar to downloading source
build-dep causes apt-get to install/remove packages in an
attempt to satisfy the build dependencies for a source packages. Right
now virtual package build depends choose a package at random.
check is a diagnostic tool; it updates the package cache and checks
for broken dependencies.
clean clears out the local repository of retrieved package
files. It removes everything but the lock file from
/var/cache/apt/archive/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.
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 off.
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.
Download only; package files are only retrieved, not unpacked or installed.
Configuration Item: APT::Get::Download-Only.
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 soltion. Any Package that are specified
must completly 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.
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
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
Configuration Item: APT::Get::Download.
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
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 or removing an essential package occurs then apt-get
Configuration Item: APT::Get::Assume-Yes.
Show upgraded packages; Print out a list of all packages that are to be
Configuration Item: APT::Get::Show-Upgraded.
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: APT::Ignore-Hold.
Do not upgrade packages; When used in conjunction with install
no-upgrade will prevent packages listed from being upgraded
if they are already installed.
Configuration Item: APT::Get::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/
command. Configuration Item: APT::Get::Print-URIs.
Use purge instead of remove for anything that would be removed.
Configuration Item: APT::Get::Purge.
Re-Install packages that are already installed and at the newest version.
Configuration Item: APT::Get::ReInstall.
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
Configuration Item: APT::Get::List-Cleanup.
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
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.
If any packages are to be removed apt-get immediately aborts without
Configuration Item: APT::Get::Remove
Only has meaning for the source command. indicates that the
given source names are not to be mapped through the binary table.
Configuration Item: APT::Get::Only-Source
Download only the diff or tar file of a source archive.
Configuration Item: APT::Get::Diff-Only and
Show a short usage summary.
Show the program verison.
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.
Set a Configuration Option; This will set an arbitary configuration
option. The syntax is -o Foo::Bar=bar.
locations to fetch packages from.
Configuration Item: Dir::Etc::SourceList.