Provided by: apt_1.2.10ubuntu1_amd64 bug

NAME

       apt-cache - query the APT cache

SYNOPSIS

       apt-cache [-agipns] [-o=config_string] [-c=config_file] {gencaches | showpkg pkg...  |
                 showsrc pkg...  | stats | dump | dumpavail | unmet | search regex...  |
                 show pkg [{=pkg_version_number | /target_release}]...  |
                 depends pkg [{=pkg_version_number | /target_release}]...  |
                 rdepends pkg [{=pkg_version_number | /target_release}]...  | pkgnames [prefix]
                 | dotty pkg [{=pkg_version_number | /target_release}]...  |
                 xvcg pkg [{=pkg_version_number | /target_release}]...  | policy [pkg...]  |
                 madison pkg...  | {-v | --version} | {-h | --help}}

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. The metadata is acquired and updated via the
       'update' command of e.g.  apt-get, so that it can be outdated if the last update is too
       long ago, but in exchange apt-cache works independently of the availability of the
       configured sources (e.g. offline).

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

       gencaches
           gencaches creates APT's package cache. This is done implicitly by all commands needing
           this cache if it is missing or outdated.

       showpkg pkg...
           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
               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 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 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. If
               more than one distribution is being accessed (for instance, "stable" and
               "unstable"), 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...
           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
           package. Use --only-source to display only source package names.

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

       search 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 and provided packages are.

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

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

       rdepends pkg...
           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...
           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 virtual
           packages are triangles, mixed virtual packages 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...
           The same as dotty, only for xvcg from the VCG tool[2].

       policy [pkg...]
           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...
           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.

       --no-pre-depends, --no-depends, --no-recommends, --no-suggests, --no-conflicts,
       --no-breaks, --no-replaces, --no-enhances
           Per default the depends and rdepends print all dependencies. This can be tweaked with
           these flags which will omit the specified dependency type. Configuration Item:
           APT::Cache::ShowDependencyType e.g.  APT::Cache::ShowRecommends.

       --implicit
           Per default depends and rdepends print only dependencies explicitly expressed in the
           metadata. With this flag it will also show dependencies implicitely added based on the
           encountered data. A Conflicts: foo e.g. expresses implicitely that this package also
           conflicts with the package foo from any other architecture. Configuration Item:
           APT::Cache::ShowImplicit.

       -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 be 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 and provided 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. If configuration settings
           need to be set before the default configuration files are parsed specify a file with
           the APT_CONFIG environment variable. See apt.conf(5) for syntax information.

       -o, --option
           Set a Configuration Option; This will set an arbitrary configuration option. The
           syntax is -o Foo::Bar=bar.  -o and --option can be used multiple times to set
           different options.

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
           (partial will be implicitly appended)

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