apt/doc/apt-get.8.yo

mailto(apt@packages.debian.org)
manpage(apt-get)(8)(4 Dec 1998)(apt)()
manpagename(apt-get)(APT package handling utility -- command-line interface)

manpagesynopsis()
  apt-get [options] [command] [package ...]

manpagedescription()

apt-get is the command-line tool for handling packages, and may be considered 
the user's "back-end" to apt(8).

em(command) is one of:
itemize(
  it() update
  it() upgrade
  it() dselect-upgrade
  it() dist-upgrade
  it() install
  it() remove
  it() check
  it() clean
)

Unless the -h, or --help option is given one of the above commands
must be present. Only the install command requires any further arguments.

startdit()
dit(bf(update))
bf(update) is used to resynchronize the package overview files from their
sources. The overviews of available packages are fetched from the
location(s) specified in bf(/etc/apt/sources.list).
For example, when using a Debian archive, this command retrieves and
scans the bf(Packages.gz) files, so that information about new and updated 
packages is available. An bf(update) should always be performed before an
bf(upgrade) bf(dist-upgrade).

dit(bf(upgrade))
bf(upgrade) is used to install the newest versions of all packages currently 
installed on the system from the sources enumerated in
bf(/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 bf(update) must be performed first so that
bf(apt-get) knows that new versions of packages are available.

dit(bf(dselect-upgrade))
bf(dselect-upgrade)
is used in conjunction with the traditional Debian GNU/Linux packaging
front-end, bf(dselect (8)). bf(dselect-upgrade)
follows the changes made by bf(dselect) to the em(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

dit(bf(dist-upgrade))
bf(dist-upgrade),in addition to performing the function of bf(upgrade),
also intelligently handles changing dependencies with new versions of
packages; bf(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 bf(/etc/apt/sources.list) file contains a 
list of locations from which to retrieve desired package files.

dit(bf(install))
bf(install) is followed by one or more em(packages) desired for installation. 
Each em(package) is a package name, not a fully qualified filename 
(for instance, in a Debian GNU/Linux system, em(lsdo) would be the argument 
provided, not em(ldso_1.9.6-2.deb)). All packages required by the package(s) 
specified for installation will also be retrieved and installed. The
bf(/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. This latter feature 
may be used to override decisions made by apt-get's conflict resolution system.

dit(bf(check))
bf(check) is a diagnostic tool; it updates the package cache and checks for 
brokenpackages.

dit(bf(clean))
df(clean) clears out the local repository of retrieved package files. It 
removes everything but the lock file from bf(/var/cache/apt/archives/)
and bf(/var/cache/apt/archives/partial/).
When APT is used as a bf(dselect(8)) method, bf(clean) is run automatically.
Those who do not use dselect will likely want to run code(apt-get clean)
from time to time to free up disk space.
enddit()

manpageoptions()

startdit()
dit(bf(-d, --download-only))
Download only; package files are only retrieved, not unpacked or installed.

dit(bf(-f, --fix-broken))
Fix; attempt to correct a system with broken dependencies in            
place. This option may be used alone or in conjunction with any of the  
command actions, and 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 or dpkg --remove to eliminate some of the offending 
packages). Use of this option together with -m may produce an error in
some situations.

dit(bf(-h, --help))
Help; display a helpful usage message and exits.

dit(bf(-m, --ignore-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 is discouraged.

dit(bf(-q, --silent))
Quiet; produces output suitable for logging, omitting progress indicators.
More qs will produce more quite up to a maximum of 2. You can also use
bf(-q=#) to set the quiet level, overriding the configuration file.

dit(bf(-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.

dit(bf(-y, --yes, --assume-yes))
Automatic yes to prompts; assume "yes" as answer to all prompts and run
non-interactively. If an undesireable situation, such as changing a held
package or removing an essential package occures then bf(apt-get) will
abort.

dit(bf(-u, --show-upgraded))
Show upgraded packages; Print out a list of all packages that are to be
upgraded.

dit(bf(--ignore-hold))
Ignore package Holds; This causes bf(apt-get) to ignore a hold placed on 
a package. This may be usefull in conjunction with bf(dist-upgrade) to
override a large number of undesired holds.

dit(bf(--no-upgrade))
Do not upgrade packages; When used in conjunction with bf(install)
bf(no-upgrade) will prevent packages listed from being upgraded if they
are already installed.

dit(bf(--force-yes))
Force yes; This is a dangerous option that will cause apt to continue without
prompting if it is doing something potentially harmfull. It should not be used
except in very special situations. Using bf(force-yes) can potentially destroy
your system!

dit(bf(-c, --config-file))
Configuration File; Specify a configuration file to use. bf(apt-get) will
read the default configuration file and then this configuration file. See
bf(apt.conf(5)) for syntax information.

dit(bf(-o, --option))
Set a Configuration Option; This will set an arbitary configuration option.
The syntax is 
verb(-o Foo::Bar=bar)

manpagefiles()
itemize(
  it() /etc/apt/sources.list 
  locations to fetch packages from
  
  it() /var/cache/apt/archives/
  storage area for retrieved package files
  
  it() /var/cache/apt/archives/partial/
  storage area for package files in transit
  
  it() /var/state/apt/lists/
  storage area for state information for each package resource specified in
  
  it() /var/state/apt/lists/partial/
  storage area for state information in transit
)

manpageseealso()
apt-cache (8),
dpkg (8),
dselect (8),
sources.list (5)

manpagediagnostics()
apt-get returns zero on normal operation, decimal 100 on error.

manpagebugs()
See http://www.debian.org/Bugs/db/pa/lapt.html.  If you wish to report a
bug in bf(apt-get), please see bf(/usr/doc/debian/bug-reporting.txt)
or the bf(bug(1)) command.

manpageauthor()
apt-get was written by the APT team <apt@packages.debian.org>.