Monday, July 19, 2010

Man Page of ldd

NAME


ldd - print shared library dependencies

SYNOPSIS

ldd [OPTION]... FILE...

DESCRIPTION

ldd prints the shared libraries required by each program or shared
library specified on the command line.

OPTIONS

--version
Print the version number of ldd.

-v --verbose
Print all information, including e.g. symbol versioning informa-
tion.

-d --data-relocs
Perform relocations and report any missing objects (ELF only).

-r --function-relocs
Perform relocations for both data objects and functions, and
report any missing objects or functions (ELF only).

--help Usage information.

BUGS

ldd does not work on a.out shared libraries.

ldd does not work with some extremely old a.out programs which were
built before ldd support was added to the compiler releases. If you
use ldd on one of these programs, the program will attempt to run with
argc = 0 and the results will be unpredictable.

AUTHOR

Roland McGrath and Ulrich Drepper.

SEE ALSO

ldconfig(8), ld.so(8).

30 October 2000 LDD(1)

/proc Folder Usage

Identify the I/O address range being used by device
cat /proc/ioports
List which registered ISA DMA channels is in use
cat /proc/dma
Display the current RAM useage
cat /proc/meminfo
List the various character and block devices currently configured (not including devices whose modules are not loaded).
cat /proc/devices
Identify the model information of cpu which used in the system
cat /proc/cpuinfo
Identify the parameters which passed to the kernel at boot time.
cat /proc/cmdline
List all currently loaded kernel modules
cat /proc/modules or /sbin/lsmod (more user friendly)
List IRQ usage of kernel drivers
cat /proc/interrupts


Back to linux LPIC1 Exam Objectives

Monday, July 12, 2010

man page of dpkg-reconfigure

NAME
       dpkg-reconfigure - reconfigure an already installed package

SYNOPSIS
        dpkg-reconfigure [options] packages

DESCRIPTION
       dpkg-reconfigure reconfigures packages after they have already been
       installed. Pass it the names of a package or packages to reconfigure.
       It will ask configuration questions, much like when the package was
       first installed.

       If you just want to see the current configuration of a package, see
       debconf-show(1) instead.

OPTIONS
       -ftype, --frontend=type
           Select the frontend to use. The default frontend can be permanently
           changed by:

            dpkg-reconfigure debconf

           Note that if you normally have debconf set to use the
           noninteractive frontend, dpkg-reconfigure will use the dialog
           frontend instead, so you actually get to reconfigure the package.

       -pvalue, --priority=value
           Specify the minimum priority of question that will be displayed.
           dpkg-reconfigure normally shows low priority questions no matter
           what your default priority is. See debconf(7) for a list.

       --default-priority
           Use whatever the default priority of question is, instead of
           forcing the priority to low.

       -a, --all
           Reconfigure all installed packages that use debconf. Warning: this
           may take a long time.

       -u, --unseen-only
           By default, all questions are shown, even if they have already been
           answered. If this parameter is set though, only questions that have
           not yet been seen will be asked.

       --force
           Force dpkg-reconfigure to reconfigure a package even if the package
           is in an inconsistent or broken state. Use with caution.

       --no-reload
           Prevent dpkg-reconfigure from reloading templates. Use with
           caution; this will prevent dpkg-reconfigure from repairing broken
           templates databases.  However, it may be useful in constrained
           environments where rewriting the templates database is expensive.

       -h, --help
           Display usage help.

SEE ALSO
       debconf(7)

AUTHOR
       Joey Hess



                                  2009-11-10               DPKG-RECONFIGURE(8)

man page of apt-get

NAME
       apt-get - APT package handling utility -- command-line interface

SYNOPSIS
       apt-get [-sqdyfmubV] [-o= config_string ] [-c= config_file ]
               [-t= { target_release_name | target_release_number_expression | target_release_codename }]
               {update | upgrade | dselect-upgrade | dist-upgrade |
               install pkg [ { =pkg_version_number | /target_release_name | /target_release_codename } ] ...
               | remove pkg...  | purge pkg...  |
               source pkg [ { =pkg_version_number | /target_release_name | /target_release_codename } ] ...
               | build-dep pkg...  | check | clean | autoclean | autoremove |
               {-v | --version} | {-h | --help}}

DESCRIPTION
       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.
       Several "front-end" interfaces exist, such as dselect(1), aptitude(8),
       synaptic(8), gnome-apt(1) and wajig(1).

       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(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
           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
           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,
           unstable).

           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 installed.

           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. 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 removed.

       purge
           purge is identical to remove except that packages are removed and
           purged (any configuration files are deleted too).

       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 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, 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(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.

       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.

       --no-install-recommends
           Do not consider recommended packages as a dependency for
           installing. Configuration Item: APT::Install-Recommends.

       -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. 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.

       --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.

       -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: 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.

       --install-recommends
           Also install recommended packages.

       --no-install-recommends
           Do not install recommended packages.

       --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.  remove --purge is equivalent to the purge
           command. 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. 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.

       --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 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. 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.

FILES
       /etc/apt/sources.list
           Locations to fetch packages from. Configuration Item:
           Dir::Etc::SourceList.

       /etc/apt/sources.list.d/
           File fragments for locations to fetch packages from. Configuration
           Item: Dir::Etc::SourceParts.

       /etc/apt/apt.conf
           APT configuration file. Configuration Item: Dir::Etc::Main.

       /etc/apt/apt.conf.d/
           APT configuration file fragments. Configuration Item:
           Dir::Etc::Parts.

       /etc/apt/preferences
           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.

       /etc/apt/preferences.d/
           File fragments for the version preferences. Configuration Item:
           Dir::Etc::PreferencesParts.

       /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).

SEE ALSO
       apt-cache(8), apt-cdrom(8), dpkg(1), dselect(1), sources.list(5),
       apt.conf(5), apt-config(8), apt-secure(8), The APT User's guide in
       /usr/share/doc/apt-doc/, apt_preferences(5), the APT Howto.

DIAGNOSTICS
       apt-get returns zero on normal operation, decimal 100 on error.

ORIGINAL AUTHORS
       Jason Gunthorpe

CURRENT AUTHORS
       APT team

       QA Page[1]

BUGS
       APT bug page[2]. If you wish to report a bug in APT, please see
       /usr/share/doc/debian/bug-reporting.txt or the reportbug(1) command.

AUTHORS
       Jason Gunthorpe

       APT team

NOTES
        1. QA Page
           http://packages.qa.debian.org/a/apt.html

        2. APT bug page
           http://bugs.debian.org/src:apt



Linux                          08 November 2008                     APT-GET(8)

man page of apt-cache

NAME
       apt-cache - APT package handling utility -- cache manipulator

SYNOPSIS
       apt-cache [-hvsn] [-o=config string] [-c=file] {[add file...] |
                 [gencaches] | [showpkg pkg...] | [showsrc pkg...] | [stats] |
                 [dump] | [dumpavail] | [unmet] | [search regex] |
                 [show pkg...] | [depends pkg...] | [rdepends pkg...] |
                 [pkgnames prefix] | [dotty pkg...] | [xvcg pkg...] |
                 [policy pkgs...] | [madison pkgs...]}

DESCRIPTION
       apt-cache performs a variety of operations on APT's package cache.
       apt-cache does not manipulate the state of the system but does provide
       operations to search and generate interesting output from the package
       metadata.

       Unless the -h, or --help option is given, one of the commands below
       must be present.

       add file(s)
           add adds the named package index files to the package cache. This
           is for debugging only.

       gencaches
           gencaches performs the same operation as apt-get check. It builds
           the source and package caches from the sources in sources.list(5)
           and from /var/lib/dpkg/status.

       showpkg pkg(s)
           showpkg displays information about the packages listed on the
           command line. Remaining arguments are package names. The available
           versions and reverse dependencies of each package listed are
           listed, as well as forward dependencies for each version. Forward
           (normal) dependencies are those packages upon which the package in
           question depends; reverse dependencies are those packages that
           depend upon the package in question. Thus, forward dependencies
           must be satisfied for a package, but reverse dependencies need not
           be. For instance, apt-cache showpkg libreadline2 would produce
           output similar to the following:

               Package: libreadline2
               Versions: 2.1-12(/var/state/apt/lists/foo_Packages),
               Reverse Depends:
                 libreadlineg2,libreadline2
                 libreadline2-altdev,libreadline2
               Dependencies:
               2.1-12 - libc5 (2 5.4.0-0) ncurses3.0 (0 (null))
               Provides:
               2.1-12 -
               Reverse Provides:
           Thus it may be seen that libreadline2, version 2.1-12, depends on
           libc5 and ncurses3.0 which must be installed for libreadline2 to
           work. In turn, libreadlineg2 and libreadline2-altdev depend on
           libreadline2. If libreadline2 is installed, libc5 and ncurses3.0
           (and ldso) must also be installed; libreadlineg2 and
           libreadline2-altdev do not have to be installed. For the specific
           meaning of the remainder of the output it is best to consult the
           apt source code.

       stats
           stats displays some statistics about the cache. No further
           arguments are expected. Statistics reported are:

           ·   Total package names is the number of package names found in the
               cache.

           ·   Normal packages is the number of regular, ordinary package
               names; these are packages that bear a one-to-one correspondence
               between their names and the names used by other packages for
               them in dependencies. The majority of packages fall into this
               category.

           ·   Pure virtual packages is the number of packages that exist only
               as a virtual package name; that is, packages only "provide" the
               virtual package name, and no package actually uses the name.
               For instance, "mail-transport-agent" in the Debian GNU/Linux
               system is a pure virtual package; several packages provide
               "mail-transport-agent", but there is no package named
               "mail-transport-agent".

           ·   Single virtual packages is the number of packages with only one
               package providing a particular virtual package. For example, in
               the Debian GNU/Linux system, "X11-text-viewer" is a virtual
               package, but only one package, xless, provides
               "X11-text-viewer".

           ·   Mixed virtual packages is the number of packages that either
               provide a particular virtual package or have the virtual
               package name as the package name. For instance, in the Debian
               GNU/Linux system, "debconf" is both an actual package, and
               provided by the debconf-tiny package.

           ·   Missing is the number of package names that were referenced in
               a dependency but were not provided by any package. Missing
               packages may be an evidence if a full distribution is not
               accessed, or if a package (real or virtual) has been dropped
               from the distribution. Usually they are referenced from
               Conflicts or Breaks statements.

           ·   Total distinct versions is the number of package versions found
               in the cache; this value is therefore at least equal to the
               number of total package names. If more than one distribution
               (both "stable" and "unstable", for instance), is being
               accessed, this value can be considerably larger than the number
               of total package names.

           ·   Total dependencies is the number of dependency relationships
               claimed by all of the packages in the cache.


       showsrc pkg(s)
           showsrc displays all the source package records that match the
           given package names. All versions are shown, as well as all records
           that declare the name to be a Binary.

       dump
           dump shows a short listing of every package in the cache. It is
           primarily for debugging.

       dumpavail
           dumpavail prints out an available list to stdout. This is suitable
           for use with dpkg(1) and is used by the dselect(1) method.

       unmet
           unmet displays a summary of all unmet dependencies in the package
           cache.

       show pkg(s)
           show performs a function similar to dpkg --print-avail; it displays
           the package records for the named packages.

       search regex [ regex ... ]
           search performs a full text search on all available package lists
           for the POSIX regex pattern given, see regex(7). It searches the
           package names and the descriptions for an occurrence of the regular
           expression and prints out the package name and the short
           description, including virtual package names. If --full is given
           then output identical to show is produced for each matched package,
           and if --names-only is given then the long description is not
           searched, only the package name is.

           Separate arguments can be used to specify multiple search patterns
           that are and'ed together.

       depends pkg(s)
           depends shows a listing of each dependency a package has and all
           the possible other packages that can fulfill that dependency.

       rdepends pkg(s)
           rdepends shows a listing of each reverse dependency a package has.

       pkgnames [ prefix ]
           This command prints the name of each package APT knows. The
           optional argument is a prefix match to filter the name list. The
           output is suitable for use in a shell tab complete function and the
           output is generated extremely quickly. This command is best used
           with the --generate option.

           Note that a package which APT knows of is not necessarily available
           to download, installable or installed, e.g. virtual packages are
           also listed in the generated list.

       dotty pkg(s)
           dotty takes a list of packages on the command line and generates
           output suitable for use by dotty from the GraphViz[1] package. The
           result will be a set of nodes and edges representing the
           relationships between the packages. By default the given packages
           will trace out all dependent packages; this can produce a very
           large graph. To limit the output to only the packages listed on the
           command line, set the APT::Cache::GivenOnly option.

           The resulting nodes will have several shapes; normal packages are
           boxes, pure provides are triangles, mixed provides are diamonds,
           missing packages are hexagons. Orange boxes mean recursion was
           stopped [leaf packages], blue lines are pre-depends, green lines
           are conflicts.

           Caution, dotty cannot graph larger sets of packages.

       xvcg pkg(s)
           The same as dotty, only for xvcg from the VCG tool[2].

       policy [ pkg(s) ]
           policy is meant to help debug issues relating to the preferences
           file. With no arguments it will print out the priorities of each
           source. Otherwise it prints out detailed information about the
           priority selection of the named package.

       madison /[ pkg(s) ]
           apt-cache's madison command attempts to mimic the output format and
           a subset of the functionality of the Debian archive management
           tool, madison. It displays available versions of a package in a
           tabular format. Unlike the original madison, it can only display
           information for the architecture for which APT has retrieved
           package lists (APT::Architecture).

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.

       -p, --pkg-cache
           Select the file to store the package cache. The package cache is
           the primary cache used by all operations. Configuration Item:
           Dir::Cache::pkgcache.

       -s, --src-cache
           Select the file to store the source cache. The source is used only
           by gencaches and it stores a parsed version of the package
           information from remote sources. When building the package cache
           the source cache is used to avoid reparsing all of the package
           files. Configuration Item: Dir::Cache::srcpkgcache.

       -q, --quiet
           Quiet; produces output suitable for logging, omitting progress
           indicators. More q's will produce more quietness up to a maximum of
           2. You can also use -q=# to set the quietness level, overriding the
           configuration file. Configuration Item: quiet.

       -i, --important
           Print only important dependencies; for use with unmet and depends.
           Causes only Depends and Pre-Depends relations to be printed.
           Configuration Item: APT::Cache::Important.

       -f, --full
           Print full package records when searching. Configuration Item:
           APT::Cache::ShowFull.

       -a, --all-versions
           Print full records for all available versions. This is the default;
           to turn it off, use --no-all-versions. If --no-all-versions is
           specified, only the candidate version will displayed (the one which
           would be selected for installation). This option is only applicable
           to the show command. Configuration Item: APT::Cache::AllVersions.

       -g, --generate
           Perform automatic package cache regeneration, rather than use the
           cache as it is. This is the default; to turn it off, use
           --no-generate. Configuration Item: APT::Cache::Generate.

       --names-only, -n
           Only search on the package names, not the long descriptions.
           Configuration Item: APT::Cache::NamesOnly.

       --all-names
           Make pkgnames print all names, including virtual packages and
           missing dependencies. Configuration Item: APT::Cache::AllNames.

       --recurse
           Make depends and rdepends recursive so that all packages mentioned
           are printed once. Configuration Item: APT::Cache::RecurseDepends.

       --installed
           Limit the output of depends and rdepends to packages which are
           currently installed. Configuration Item: APT::Cache::Installed.

       -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 arbitrary
           configuration option. The syntax is -o Foo::Bar=bar.  -o and
           --option can be used multiple times to set different options.

FILES
       /etc/apt/sources.list
           Locations to fetch packages from. Configuration Item:
           Dir::Etc::SourceList.

       /etc/apt/sources.list.d/
           File fragments for locations to fetch packages from. Configuration
           Item: Dir::Etc::SourceParts.

       /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).

SEE ALSO
       apt.conf(5), sources.list(5), apt-get(8)

DIAGNOSTICS
       apt-cache returns zero on normal operation, decimal 100 on error.

BUGS
       APT bug page[3]. If you wish to report a bug in APT, please see
       /usr/share/doc/debian/bug-reporting.txt or the reportbug(1) command.

AUTHORS
       Jason Gunthorpe

       APT team

NOTES
        1. GraphViz
           http://www.research.att.com/sw/tools/graphviz/

        2. VCG tool
           http://rw4.cs.uni-sb.de/users/sander/html/gsvcg1.html

        3. APT bug page
           http://bugs.debian.org/src:apt



Linux                          29 February 2004                   APT-CACHE(8)

man page of dpkg

NAME
       dpkg - package manager for Debian

SYNOPSIS
       dpkg [options] action

WARNING
       This  manual is intended for users wishing to understand dpkg's command
       line options and package states in more detail than  that  provided  by
       dpkg --help.

       It  should not be used by package maintainers wishing to understand how
       dpkg will install their packages. The descriptions of  what  dpkg  does
       when installing and removing packages are particularly inadequate.

DESCRIPTION
       dpkg  is  a  tool to install, build, remove and manage Debian packages.
       The primary and more user-friendly front-end for dpkg  is  aptitude(1).
       dpkg  itself  is controlled entirely via command line parameters, which
       consist of exactly one action and zero or  more  options.  The  action-
       parameter tells dpkg what to do and options control the behavior of the
       action in some way.

       dpkg can also be used as a front-end to dpkg-deb(1).  The following are
       dpkg-deb  actions, and if they are encountered, dpkg just runs dpkg-deb
       with the parameters given to it:
           -b, --build,
           -c, --contents,
           -I, --info,
           -f, --field,
           -e, --control,
           -x, --extract,
           -X, --vextract, and
           --fsys-tarfile.
       Please refer to dpkg-deb(1) for information about these actions.

INFORMATION ABOUT PACKAGES
       dpkg maintains some usable information about  available  packages.  The
       information  is  divided in three classes: states, selection states and
       flags. These values are intended to be changed mainly with dselect.

   PACKAGE STATES
       not-installed
              The package is not installed on your system.

       config-files
              Only the configuration files of the package exist on the system.

       half-installed
              The installation of the package has been started, but  not  com‐
              pleted for some reason.

       unpacked
              The package is unpacked, but not configured.

       half-configured
              The  package is unpacked and configuration has been started, but
              not yet completed for some reason.

       triggers-awaited
              The package awaits trigger processing by another package.

       triggers-pending
              The package has been triggered.

       installed
              The package is unpacked and configured OK.

   PACKAGE SELECTION STATES
       install
              The package is selected for installation.

       hold   A package marked to be on hold is not handled  by  dpkg,  unless
              forced to do that with option --force-hold.

       deinstall
              The  package  is  selected  for  deinstallation (i.e. we want to
              remove all files, except configuration files).

       purge  The package is selected to be purged (i.e.  we  want  to  remove
              everything, even configuration files).

   PACKAGE FLAGS
       reinst-required
              A  package  marked  reinst-required is broken and requires rein‐
              stallation. These packages cannot be removed, unless forced with
              option --force-remove-reinstreq.

ACTIONS
       -i, --install package_file...
              Install  the  package. If --recursive or -R option is specified,
              package_file must refer to a directory instead.

              Installation consists of the following steps:

              1. Extract the control files of the new package.

              2. If another version of the same package was  installed  before
              the new installation, execute prerm script of the old package.

              3. Run preinst script, if provided by the package.

              4.  Unpack  the  new files, and at the same time back up the old
              files, so that if something goes wrong, they can be restored.

              5. If another version of the same package was  installed  before
              the new installation, execute the postrm script of the old pack‐
              age. Note that this script is executed after the preinst  script
              of  the  new  package, because new files are written at the same
              time old files are removed.

              6. Configure the package. See --configure for detailed  informa‐
              tion about how this is done.

       --unpack package_file...
              Unpack the package, but don't configure it. If --recursive or -R
              option is specified, package_file  must  refer  to  a  directory
              instead.

       --configure package...|-a|--pending
              Reconfigure  an  unpacked  package.  If -a or --pending is given
              instead of package, all unpacked but unconfigured  packages  are
              configured.

              Configuring consists of the following steps:

              1.  Unpack  the  conffiles, and at the same time back up the old
              conffiles, so that they can be restored if something goes wrong.

              2. Run postinst script, if provided by the package.

       --triggers-only package...|-a|--pending
              Processes only triggers. All pending triggers will be processed.
              If package names are supplied only those packages' triggers will
              be processed, exactly once each where  necessary.  Use  of  this
              option  may  leave packages in the improper triggers-awaited and
              triggers-pending states. This can be  fixed  later  by  running:
              dpkg --configure --pending.

       -r, --remove, -P, --purge package...|-a|--pending
              Remove  an  installed  package. -r or --remove remove everything
              except conffiles. This may avoid having to reconfigure the pack‐
              age  if  it  is  reinstalled later. (Conffiles are configuration
              files that are listed in the DEBIAN/conffiles control file).  -P
              or  --purge  removes  everything,  including conffiles. If -a or
              --pending is given instead of a package name, then all  packages
              unpacked,   but   marked   to  be  removed  or  purged  in  file
              /var/lib/dpkg/status, are removed or purged, respectively. Note:
              some  configuration  files might be unknown to dpkg because they
              are created and handled  separately  through  the  configuration
              scripts. In that case, dpkg won't remove them by itself, but the
              package's postrm script (which is called by dpkg), has  to  take
              care of their removal during purge.

              Removing of a package consists of the following steps:

              1. Run prerm script

              2. Remove the installed files

              3. Run postrm script

       --update-avail, --merge-avail Packages-file
              Update  dpkg's  and  dselect's idea of which packages are avail‐
              able. With action --merge-avail,  old  information  is  combined
              with information from Packages-file. With action --update-avail,
              old information is replaced with the information  in  the  Pack‐
              ages-file.  The  Packages-file distributed with Debian is simply
              named Packages. dpkg keeps its record of available  packages  in
              /var/lib/dpkg/available.

              A  simpler one-shot command to retrieve and update the available
              file is dselect update. Note that this file is mostly useless if
              you don't use dselect but an APT-based frontend: APT has its own
              system to keep track of available packages.

       -A, --record-avail package_file...
              Update dpkg and dselect's idea of which packages  are  available
              with  information  from the package package_file. If --recursive
              or -R option is specified, package_file must refer to  a  direc‐
              tory instead.

       --forget-old-unavail
              Now obsolete and a no-op as dpkg will automatically forget unin‐
              stalled unavailable packages.

       --clear-avail
              Erase the existing information about what  packages  are  avail‐
              able.

        -C, --audit
              Searches for packages that have been installed only partially on
              your system. dpkg will suggest what to do with them to get  them
              working.

       --get-selections [package-name-pattern...]
              Get  list of package selections, and write it to stdout. Without
              a pattern, non-installed packages (i.e. those  which  have  been
              previously purged) will not be shown.

       --set-selections
              Set  package  selections  using  file read from stdin. This file
              should be in the format ' ', where state is  one
              of  install,  hold,  deinstall or purge. Blank lines and comment
              lines beginning with '#' are also permitted.

       --clear-selections
              Set the requested state of every non-essential package to  dein‐
              stall.    This   is  intended  to  be  used  immediately  before
              --set-selections, to deinstall any packages not in list given to
              --set-selections.

       --yet-to-unpack
              Searches  for  packages selected for installation, but which for
              some reason still haven't been installed.


       --print-architecture
              Print architecture of packages dpkg installs  (for  exam‐
              ple, "i386").

       --compare-versions ver1 op ver2
              Compare  version  numbers, where op is a binary operator.
              dpkg returns success (zero result) if the specified  con‐
              dition  is satisfied, and failure (nonzero result) other‐
              wise. There are two groups of operators, which differ  in
              how  they  treat  an  empty  ver1 or ver2. These treat an
              empty version as earlier than any version: lt le eq ne ge
              gt.  These  treat an empty version as later than any ver‐
              sion: lt-nl le-nl ge-nl gt-nl. These  are  provided  only
              for  compatibility with control file syntax: < << <= = >=
              >> >.

       --command-fd
              Accept a series of commands on input file descriptor .
              Note:  additional  options  set  on the command line, and
              thru this file descriptor, are not reset  for  subsequent
              commands executed during the same run.

       --help Display a brief help message.

       --force-help
              Give help about the --force-thing options.

       -Dh, --debug=help
              Give help about debugging options.

       --licence, --license
              Display dpkg licence.

       --version
              Display dpkg version information.

       dpkg-deb actions
              See  dpkg-deb(1) for more information about the following
              actions.

              -b, --build directory [archive|directory]
                  Build a deb package.
              -c, --contents archive
                  List contents of a deb package.
              -e, --control filename [directory]
                  Extract control-information from a package.
              -x, --extract archive directory
                  Extract the files contained by package.
              -X, --vextract archive directory
                  Extract and display the filenames contained by a
                  package.
              -f, --field  archive [control-field...]
                  Display control field(s) of a package.
              --fsys-tarfile archive
                  Display the filesystem tar-file contained by a
                  Debian package.
              -I, --info archive [control-file...]
                  Show information about a package.


       dpkg-query actions
              See dpkg-query(1) for more information about the  follow‐
              ing actions.


              -l, --list package-name-pattern...
                  List packages matching given pattern.
              -s, --status package-name...
                  Report status of specified package.
              -L, --listfiles package-name...
                  List files installed to your system from package-name.
              -S, --search filename-search-pattern...
                  Search for a filename from installed packages.
              -p, --print-avail package-name...
                  Display details about package-name, as found in
                  /var/lib/dpkg/available. Users of APT-based frontends
                  should use apt-cache show package-name instead.

OPTIONS
       All options can be specified both on the command line and in the
       dpkg configuration file /etc/dpkg/dpkg.cfg or the files  on  the
       configuration  directory /etc/dpkg/dpkg.cfg.d/. Each line in the
       configuration file is either an option (exactly the same as  the
       command line option but without leading dashes) or a comment (if
       it starts with a #).

       --abort-after=number
              Change after how many errors dpkg will abort. The default
              is 50.

       -B, --auto-deconfigure
              When  a  package  is removed, there is a possibility that
              another installed package depended on the  removed  pack‐
              age.  Specifying  this option will cause automatic decon‐
              figuration of the package which depended on  the  removed
              package.

       -Doctal, --debug=octal
              Switch  debugging  on.  octal is formed by bitwise-orring
              desired values together from the list  below  (note  that
              these  values  may  change  in  future  releases). -Dh or
              --debug=help display these debugging values.

                  number  description
                       1   Generally helpful progress information
                       2   Invocation and status of maintainer scripts
                      10   Output for each file processed
                     100   Lots of output for each file processed
                      20   Output for each configuration file
                     200   Lots of output for each configuration file
                      40   Dependencies and conflicts
                     400   Lots of dependencies/conflicts output
                   10000   Trigger activation and processing
                   20000   Lots of output regarding triggers
                   40000   Silly amounts of output regarding triggers
                    1000   Lots of drivel about e.g. the dpkg/info dir
                    2000   Insane amounts of drivel

       --force-things, --no-force-things, --refuse-things

              Force or refuse (no-force and refuse mean the same thing)
              to  do  some  things. things is a comma separated list of
              things specified below. --force-help displays  a  message
              describing  them.   Things  marked with (*) are forced by
              default.

              Warning: These options are mostly intended to be used  by
              experts  only.  Using  them  without  fully understanding
              their effects may break your whole system.

              all: Turns on (or off) all force options.

              downgrade(*): Install a package, even if newer version of
              it is already installed.

              Warning:  At  present  dpkg  does  not  do any dependency
              checking on downgrades and therefore will not warn you if
              the  downgrade  breaks the dependency of some other pack‐
              age. This can  have  serious  side  effects,  downgrading
              essential system components can even make your whole sys‐
              tem unusable. Use with care.

              configure-any: Configure also any unpacked but  unconfig‐
              ured packages on which the current package depends.

              hold: Process packages even when marked "hold".

              remove-reinstreq:  Remove  a package, even if it's broken
              and marked to require reinstallation. This may, for exam‐
              ple,  cause parts of the package to remain on the system,
              which will then be forgotten by dpkg.

              remove-essential: Remove, even if the package is  consid‐
              ered  essential.  Essential  packages contain mostly very
              basic Unix commands. Removing them might cause the  whole
              system to stop working, so use with caution.

              depends: Turn all dependency problems into warnings.

              depends-version:  Don't care about versions when checking
              dependencies.

              breaks: Install, even if this would break  another  pack‐
              age.

              conflicts:  Install,  even  if  it conflicts with another
              package. This is dangerous, for  it  will  usually  cause
              overwriting of some files.

              confmiss: Always install a missing conffile. This is dan‐
              gerous, since it means not preserving a change (removing)
              made to the file.

              confnew:  If  a conffile has been modified always install
              the   new   version   without   prompting,   unless   the
              --force-confdef  is  also  specified,  in  which case the
              default action is preferred.

              confold: If a conffile has been modified always keep  the
              old version without prompting, unless the --force-confdef
              is also specified, in which case the  default  action  is
              preferred.

              confdef:  If  a  conffile has been modified always choose
              the default action. If there is no default action it will
              stop   to   ask   the   user  unless  --force-confnew  or
              --force-confold is also been given, in which case it will
              use that to decide the final action.

              overwrite:  Overwrite  one  package's file with another's
              file.

              overwrite-dir  Overwrite  one  package's  directory  with
              another's file.

              overwrite-diverted:  Overwrite  a  diverted  file with an
              undiverted version.

              architecture: Process even packages with the wrong archi‐
              tecture.

              bad-path: PATH is missing important programs, so problems
              are likely.

              not-root: Try to (de)install things even when not root.

              bad-verify: Install a package even if it fails authentic‐
              ity check.


       --ignore-depends=package,...
              Ignore  dependency-checking for specified packages (actu‐
              ally, checking is performed, but only warnings about con‐
              flicts are given, nothing else).

       --new, --old
              Select  new  or  old  binary  package  format.  This is a
              dpkg-deb(1) option.

       --nocheck
              Don't read or check contents of control file while build‐
              ing a package.  This is a dpkg-deb(1) option.

       --no-act, --dry-run, --simulate
              Do  everything  which  is  supposed to be done, but don't
              write any changes. This is used to see what would  happen
              with  the  specified  action,  without actually modifying
              anything.

              Be sure to give --no-act before the action-parameter,  or
              you  might  end  up  with undesirable results. (e.g. dpkg
              --purge foo --no-act will first  purge  package  foo  and
              then try to purge package --no-act, even though you prob‐
              ably expected it to actually do nothing)

       -R, --recursive
              Recursively handle all  regular  files  matching  pattern
              *.deb  found at specified directories and all of its sub‐
              directories. This can be used  with  -i,  -A,  --install,
              --unpack and --avail actions.

       -G     Don't  install  a  package if a newer version of the same
              package  is  already  installed.  This  is  an  alias  of
              --refuse-downgrade.

       --admindir=dir
              Change  default  administrative directory, which contains
              many  files  that  give  information  about   status   of
              installed  or  uninstalled  packages,  etc.  (Defaults to
              /var/lib/dpkg)

       --instdir=dir
              Change default installation directory which refers to the
              directory  where packages are to be installed. instdir is
              also the directory passed  to  chroot(2)  before  running
              package's  installation  scripts,  which  means  that the
              scripts see instdir as a root directory.  (Defaults to /)

       --root=dir
              Changing root changes instdir  to  dir  and  admindir  to
              dir/var/lib/dpkg.

       -O, --selected-only
              Only process the packages that are selected for installa‐
              tion. The actual marking is done with dselect or by dpkg,
              when  it handles packages. For example, when a package is
              removed, it will be marked selected for deinstallation.

       -E, --skip-same-version
              Don't install the package if  the  same  version  of  the
              package is already installed.

       --pre-invoke=command
       --post-invoke=command
              Set  an  invoke hook command to be run via “sh -c” before
              or after the dpkg run for the unpack, configure, install,
              triggers-only, remove and purge dpkg actions. This option
              can be specified multiple times. The  order  the  options
              are  specified  is preserved, with the ones from the con‐
              figuration  files  taking  precedence.   The  environment
              variable  DPKG_HOOK_ACTION  is  set  for the hooks to the
              current dpkg action. Note:  front-ends  might  call  dpkg
              several  times  per invocation, which might run the hooks
              more times than expected.

       --status-fd n
              Send machine-readable package status and progress  infor‐
              mation to file descriptor n. This option can be specified
              multiple times. The information is generally  one  record
              per line, in one of the following forms:

              status: package: status
                     Package status changed; status is as in the status
                     file.

              status: package : error : extended-error-message
                     An error occurred. Unfortunately at  the  time  of
                     writing  extended-error-message  can  contain new‐
                     lines, although in locales where  the  translators
                     have  not  made mistakes every newline is followed
                     by at least one space.

              status: file : conffile-prompt  :  'real-old'  'real-new'
              useredited distedited
                     User is being asked a conffile question.

              processing: stage: package
                     Sent  just before a processing stage starts. stage
                     is one  of  upgrade,  install  (both  sent  before
                     unpacking),    configure,   trigproc,   disappear,
                     remove, purge.

       --log=filename
              Log  status  change  updates  and  actions  to  filename,
              instead  of the default /var/log/dpkg.log. If this option
              is given multiple times, the last filename is  used.  Log
              messages  are  of  the  form  `YYYY-MM-DD HH:MM:SS status
                  '  for  status  change
              updates;  `YYYY-MM-DD HH:MM:SS
              version> ' for actions where 
              is  one of install, upgrade, remove, purge; and `YYYY-MM-
              DD HH:MM:SS conffile ' for  conffile
              changes where is either install or keep.

       --no-debsig
              Do not try to verify package signatures.

       --no-triggers
              Do  not  run  any  triggers in this run (activations will
              still be recorded).  If used with --configure package  or
              --triggers-only  package  then the named package postinst
              will still be run even if only a triggers run is  needed.
              Use  of  this  option  may leave packages in the improper
              triggers-awaited and triggers-pending states. This can be
              fixed later by running: dpkg --configure --pending.

       --triggers
              Cancels a previous --no-triggers.

FILES
       /etc/dpkg/dpkg.cfg
              Configuration file with default options.

       /var/log/dpkg.log
              Default  log  file  (see /etc/dpkg/dpkg.cfg(5) and option
              --log).

       The other files listed below are in their  default  directories,
       see  option  --admindir  to see how to change locations of these
       files.

       /var/lib/dpkg/available
              List of available packages.

       /var/lib/dpkg/status
              Statuses of available packages. This file contains infor‐
              mation  about whether a package is marked for removing or
              not, whether it is installed or  not,  etc.  See  section
              INFORMATION ABOUT PACKAGES for more info.

              The  status  file  is backed up daily in /var/backups. It
              can be useful if it's lost or corrupted due  to  filesys‐
              tems troubles.

       The  following  files  are  components  of a binary package. See
       deb(5) for more information about them:

       control

       conffiles

       preinst

       postinst

       prerm

       postrm

ENVIRONMENT VARIABLES
       DPKG_NO_TSTP
              Define this to something if you prefer  dpkg  starting  a
              new  shell  rather  than suspending itself, while doing a
              shell escape.

       SHELL  The program dpkg will execute when starting a new shell.

       COLUMNS
              Sets the number of columns dpkg should use when  display‐
              ing formatted text. Currently only used by -l.

       DPKG_RUNNING_VERSION
              Defined  by  dpkg on the maintainer script environment to
              the version of the currently running dpkg instance.

       DPKG_MAINTSCRIPT_PACKAGE
              Defined by dpkg on the maintainer script  environment  to
              the package name being handled.

       DPKG_MAINTSCRIPT_ARCH
              Defined  by  dpkg on the maintainer script environment to
              the architecture the package got built for.

EXAMPLES
       To list packages related to the editor vi(1):
            dpkg -l '*vi*'

       To see the entries in /var/lib/dpkg/available of two packages:
            dpkg --print-avail elvis vim | less

       To search the listing of packages yourself:
            less /var/lib/dpkg/available

       To remove an installed elvis package:
            dpkg -r elvis

       To install a package, you first need to find it in an archive or
       CDROM.  The  "available"  file  shows that the vim package is in
       section "editors":
            cd /cdrom/pool/main/v/vim
            dpkg -i vim_4.5-3.deb

       To make a local copy of the package selection states:
            dpkg --get-selections >myselections

       You might transfer this file to another computer, and install it
       there with:
            dpkg --clear-selections
            dpkg --set-selections

       Note that this will not actually install or remove anything, but
       just set the selection state on the requested packages. You will
       need some other application to actually download and install the
       requested packages. For example, run apt-get dselect-upgrade.

       Ordinarily, you will find that dselect(1) provides a more conve‐
       nient way to modify the package selection states.

ADDITIONAL FUNCTIONALITY
       Additional  functionality can be gained by installing any of the
       following packages: apt, aptitude and debsums.

SEE ALSO
       aptitude(1),  apt(1),  dselect(1),  dpkg-deb(1),  dpkg-query(1),
       deb(5), deb-control(5), dpkg.cfg(5), and dpkg-reconfigure(8).

BUGS
       --no-act usually gives less information than might be helpful.

AUTHORS
       See  /usr/share/doc/dpkg/THANKS  for the list of people who have
       contributed to dpkg.



Debian Project                    2009-11-12                           dpkg(1)