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manpage(apt-cache)(8)(4 Dec 1998)(apt)()
manpagename(apt-cache)(APT package handling utility -- cache manipulator)

manpagesynopsis()
apt-cache command [argument ...]

manpagedescription()
bf(apt-cache) performs a variety of operations on APT's package cache.
bf(apt-cache) is seldom called directly; instead its operations are
performed automatically by the other bf(apt) utilities.

em(command) is one of:
itemize(
  it() add file1 [file2] [...]
  it() gencaches
  it() showpkg package1 [package2] [...]
  it() stats
  it() dump
  it() dumpavail
  it() unmet
  it() check
  it() search
  it() show
  it() showpkg
)

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

startdit()
dit(bf(add))
bf(add) adds the names package index files to the package cache.

dit(bf(gencaches))
bf(gencaches) performs the same opration as bf(apt-get check). It builds
the source and package caches from thes sources in bf(/etc/apt/sources.list)
and from bf(/var/lib/dpkg/status).

dit(bf(showpkg))
bf(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, bf(apt-cache showpkg libreadline2) would produce output similar
to the following:

verb(
Package: libreadline2

Versions:

2.1-12(/var/state/apt/lists/debian.midco.net_debian_dists_slink_main_binary-i386_Packages),

Reverse Depends: 

  libreadlineg2,libreadline2

  libreadline2-altdev,libreadline2
Dependencies:

2.1-12 - libc5 (2 5.4.0-0) ncurses3.0 (0 (null)) ldso (2 1.9.0-1)

Provides: 

2.1-12 - 

Reverse Provides: 
)			    

Thus it may be seen that libreadline2, version 2.1-8, depends on libc5,
ncurses3.0, and ldso, which must be installed for libreadline2 to work. In
turn, libreadlineg2 and libreadline2-altdev depend on libreadline2. If
libreadline2 is installed, libc5, 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.

dit(bf(stats))
bf(stats) displays some statistics about bf(cache).
No further arguments are expected. Statistics reported are:
itemize(
   it() bf(Total package names) is the number of package names found in the cache.
   
   it() bf(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.

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

   it() bf(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, e2fsprogs is 
   both an actual package, and provided by the e2compr package.
   
   it() bf(Missing) is the number of package names that were referenced in a 
   dependency but were not provided by any package. Missing packages may be 
   in evidence if a full distribution is not accesssed, or if a package 
   (real or virtual) has been dropped from the distribution.

   it() bf(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.

   it() bf(Total dependencies) is the number of dependency relationships claimed 
   by all of the packages in the cache.
)

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

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

dit(bf(unmet))
bf(unmet) displays a summary of all unmet dependencies in the package cache.

dit(bf(check))
bf(check) is a random function for testing certain aspects of the cache.
Do not use it.

dit(bf(showpkg))
bf(showpkg) displays a listing of the given package cache structure and some
related information about it. The list is ment primarily for debugging.

dit(bf(show))
bf(show) performs the same function as dpkg --print-avail, it displays
the package records for the named packages.

dit(bf(search))
bf(search) performs a full text search on all available package files for
the pattern given. It searchs the package names and the descriptions for
an occurance of the string and prints out the package name and the short
description. If --full is given then output identical to bf(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.

enddit()

manpageoptions()
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 bf(-f-),
bf(--no-f), bf(-f=no) or several other variations.

startdit()
dit(bf(-h, --help))
Show a short usage summary.

dit(bf(-v, --version))
Show the program verison.

dit(bf(-p --pkg-cache))
Select the file to store the package cache. The package cache is the primary
cache used by all operations.
See bf(Dir::Cache::pkgcache).

dit(bf(-s --src-cache))
Select the file to store the source cache. The source is used only by
bf(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 advoid reparsing all of the package files.
See bf(Dir::Cache::srcpkgcache).

dit(bf(-q, --quiet))
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.
See bf(quiet).

dit(bf(-i --important))
Print only important deps; for use with unmet causes only em(Depends) and 
em(Pre-Depends) relations to be printed.
See bf(APT::Cache::Important).

dit(bf(-f --full))
Print full package records when searching. See bf(APT::Cache::ShowFull).

dit(bf(--names-only))
Only search on the package names, not the long description. See
bf(APT::Cache::Names-Only).

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)
enddit()

manpagefiles()
itemize(
  it() /etc/apt/sources.list 
  locations to fetch packages from
  
  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-get(8),
sources.list(5),
apt.conf(5)

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

manpagebugs()
See http://bugs.debian.org/apt.  If you wish to report a
bug in bf(apt-cache), 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>.