dpkg(1)

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 completed 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 from system directories, even configuration files).

  PACKAGE FLAGS

reinst-required
    A package marked reinst-required is broken and requires reinstallation. 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 package. 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 information 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
    Configure a package which has been unpacked but not yet configured. If -a or --pending is given instead of package, all unpacked but unconfigured packages are configured. To reconfigure a package which has already been configured, try the dpkg-reconfigure(8) command instead. 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 package 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. Of course, this only applies to files in system directories, not configuration files written to individual users' home directories. 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 available. 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 Packages-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 directory instead.

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

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

-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 '<package> <state>', 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 deinstall. 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 example, "i386").

--compare-versions ver1 op ver2
    Compare version numbers, where op is a binary operator. dpkg returns success (zero result) if the specified condition is satisfied, and failure (nonzero result) otherwise. 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 version: lt-nl le-nl ge-nl gt-nl. These are provided only for compatibility with control file syntax: < << <= = >= >> >.

--command-fd <n>
    Accept a series of commands on input file descriptor <n>. Note: additional options set on the command line, and through 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.

--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 following 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 package. Specifying this option will cause automatic deconfiguration 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 package. This can have serious side effects, downgrading essential system components can even make your whole system unusable. Use with care. configure-any: Configure also any unpacked but unconfigured 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 example, 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 considered 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 package. 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 dangerous, 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. confask: If a conffile has been modified always offer to replace it with the version in the package, even if the version in the package did not change. If any of --force-confmiss, --force-confnew, --force-confold, or --force-confdef is also given, it will be used 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. unsafe-io: Do not perform safe I/O operations when unpacking. Currently this implies not performing file system syncs before file renames, which is known to cause substantial performance degradation on some file systems, unfortunately the ones that require the safe I/O on the first place due to their unreliable behaviour causing zero-length files on abrupt system crashes. Note: For ext4, the main offender, consider using instead the mount option nodelalloc, which will fix both the performance degradation and the data safety issues, the latter by making the file system not produce zero-length files on abrupt system crashes with any software not doing syncs before atomic renames. Warning: Using this option might improve performance at the cost of losing data, use with care. architecture: Process even packages with the wrong architecture. 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 authenticity check.

--ignore-depends=package,...
    Ignore dependency-checking for specified packages (actually, checking is performed, but only warnings about conflicts 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 building 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 probably expected it to actually do nothing)

-R, --recursive
    Recursively handle all regular files matching pattern *.deb found at specified directories and all of its subdirectories. 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 installation. 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 configuration 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.

--path-exclude=glob-pattern
--path-include=glob-pattern
    Set glob-pattern as a path filter, either by excluding or re-including previously excluded paths matching the specified patterns during install. Warning: take into account that depending on the excluded paths you might completely break your system, use with caution. The glob patterns use the same wildcards used in the shell, were '*' matches any sequence of characters, including the empty string and also '/'. For example, '/usr/*/READ*' matches '/usr/share/doc/package/README'. As usual, '?' matches any single character (again, including '/'). And '[' starts a character class, which can contain a list of characters, ranges and complementations. See glob(7) for detailed information about globbing. Note: the current implementation might re-include more directories and symlinks than needed, to be on the safe side and avoid possible unpack failures, future work might fix this. This can be used to remove all paths except some particular ones; a typical case is:
    --path-exclude=/usr/share/doc/*
    --path-include=/usr/share/doc/*/copyright
    to remove all documentation files except the copyright files. These two options can be specified multiple times, and interleaved with each other. Both are processed in the given order, with the last rule that matches a file name making the decision.

--status-fd n
    Send machine-readable package status and progress information 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 newlines, 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 <state> <pkg> <installed-version>' for status change updates; `YYYY-MM-DD HH:MM:SS <action> <pkg> <installed-version> <available-version>' for actions where <action> is one of install, upgrade, remove, purge; and `YYYY-MM-DD HH:MM:SS conffile <filename> <decision>' for conffile changes where <decision> 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 information 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 filesystems 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

HOME
    If set, dpkg will use it as the directory from which to read the user specific configuration file.

TMPDIR
    If set, dpkg will use it as the directory in which to create temporary files and directories.

PAGER
    The program dpkg will execute when displaying the conffiles.

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

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

DPKG_SHELL_REASON
    Defined by dpkg on the shell spawned on the conffile prompt to examine the situation. Current valid value: conffile-prompt.

DPKG_CONFFILE_OLD
    Defined by dpkg on the shell spawned on the conffile prompt to examine the situation. Contains the path to the old conffile.

DPKG_CONFFILE_NEW
    Defined by dpkg on the shell spawned on the conffile prompt to examine the situation. Contains the path to the new conffile.

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.

DPKG_MAINTSCRIPT_NAME
    Defined by dpkg on the maintainer script environment to the name of the script running (preinst, postinst, prerm, postrm).

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 <myselections
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 convenient 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.