# dpkg

## NAME



           dpkg - package manager for Debian
    


## SYNOPSIS



           **dpkg**[_option_...] _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 medium-level tool to install, build, remove and manage
           Debian packages.  The primary and more user-friendly front-end for
           **dpkg** as a CLI (command-line interface) is **apt**(8) and as a TUI
           (terminal user interface) is **aptitude**(8).  **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) and
           dpkg-query(1).  The list of supported actions can be found later
           on in the **ACTIONS** section.  If any such action is encountered **dpkg**
           just runs **dpkg-deb** or **dpkg-query** with the parameters given to it,
           but no specific options are currently passed to them, to use any
           such option the back-ends need to be called directly.
    


## 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 or the **postrm** script and the data
               it needs to remove 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 correctly unpacked and configured.
    
       **Package selection states**
           **install**
               The package is selected for installation.
    
           **hold**
               A package marked to be on **hold** is kept on the same version,
               that is, no automatic new installs, upgrades or removals will
               be performed on them, unless these actions are requested
               explicitly, or are permitted to be done automatically with the
               **--force-hold** option.
    
           **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).
    
           **unknown**
               The package selection is unknown.  A package that is also in a
               **not-installed** state, and with an **ok** flag will be forgotten in
               the next database store.
    
       **Package flags**
           **ok** A package marked **ok** is in a known state, but might need
               further processing.
    
           **reinstreq**
               A package marked **reinstreq** 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.
    
               Will process triggers for **Pre-Depends** unless **--no-triggers** has
               been specified.
    
           **--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 (which is part of
               the **debconf** project).
    
               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.
    
               Will process triggers unless **--no-triggers** has been specified.
    
           **--triggers-only** _package_...|**-a** |**--pending**
               Processes only triggers (since dpkg 1.14.17).  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** _package_...|**-a** |**--pending**
               Remove an installed package.  This removes everything except
               conffiles and other data cleaned up by the _postrm_ script,
               which 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).  If there is no
               _DEBIAN/conffiles_ control file nor _DEBIAN/postrm_ script, this
               command is equivalent to calling **--purge**.  If **-a** or **--pending**
               is given instead of a package name, then all packages
               unpacked, but marked to be removed in file
               _/usr/local/var/lib/dpkg/status_ , are removed.
    
               Removing of a package consists of the following steps:
    
               **1.** Run _prerm_ script.
    
               **2.** Remove the installed files.
    
               **3.** Run _postrm_ script.
    
               Will process triggers unless **--no-triggers** has been specified.
    
           **-P** , **--purge** _package_...|**-a** |**--pending**
               Purge an installed or already removed package.  This removes
               everything, including conffiles, and anything else cleaned up
               from _postrm_.  If **-a** or **--pending** is given instead of a package
               name, then all packages unpacked or removed, but marked to be
               purged in file _/usr/local/var/lib/dpkg/status_ , are purged.
    
               **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.
    
               Purging of a package consists of the following steps:
    
               **1.** Remove the package, if not already removed.  See **--remove**
                   for detailed information about how this is done.
    
               **2.** Run _postrm_ script.
    
               Will process triggers unless **--no-triggers** has been specified.
    
           **-V** , **--verify**[_package-name_...]
               Verifies the integrity of _package-name_ or all packages if
               omitted, by comparing information from the files installed by
               a package with the files metadata information stored in the
               **dpkg** database (since dpkg 1.17.2).  The origin of the files
               metadata information in the database is the binary packages
               themselves.  That metadata gets collected at package unpack
               time during the installation process.
    
               Currently the only functional check performed is an md5sum
               verification of the file contents against the stored value in
               the files database.  It will only get checked if the database
               contains the file md5sum.  To check for any missing metadata
               in the database, the **--audit** command can be used.  This is
               only an integrity check and should not be considered as any
               kind of security verification.
    
               The output format is selectable with the **--verify-format**
               option, which by default uses the **rpm** format, but that might
               change in the future, and as such, programs parsing this
               command output should be explicit about the format they
               expect.
    
           **-C** , **--audit**[_package-name_...]
               Performs database sanity and consistency checks for
               _package-name_ or all packages if omitted (per package checks
               since dpkg 1.17.10).  For example, searches for packages that
               have been installed only partially on your system or that have
               missing, wrong or obsolete control data or files.  **dpkg** will
               suggest what to do with them to get them fixed.
    
           **--update-avail**[_Packages-file_]
           **--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_ ».  If the
               _Packages-file_ argument is missing or named «**-** » then it will be
               read from standard input (since dpkg 1.17.7).  **dpkg** keeps its
               record of available packages in
               _/usr/local/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 (since dpkg 1.15.4), but only
               those that do not contain user information such as package
               selections.
    
           **--clear-avail**
               Erase the existing information about what packages are
               available.
    
           **--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.
    
               The _available_ file needs to be up-to-date for this command to
               be useful, otherwise unknown packages will be ignored with a
               warning.  See the **--update-avail** and **--merge-avail** commands
               for more information.
    
           **--clear-selections**
               Set the requested state of every non-essential package to
               deinstall (since dpkg 1.13.18).  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.
    
               **Note** : This command makes use of both the available file and
               the package selections.
    
           **--predep-package**
               Print a single package which is the target of one or more
               relevant pre-dependencies and has itself no unsatisfied
               pre-dependencies.
    
               If such a package is present, output it as a Packages file
               entry, which can be massaged as appropriate.
    
               **Note** : This command makes use of both the available file and
               the package selections.
    
               Returns 0 when a package is printed, 1 when no suitable
               package is available and 2 on error.
    
           **--add-architecture** _architecture_
               Add _architecture_ to the list of architectures for which
               packages can be installed without using **--force-architecture**
               (since dpkg 1.16.2).  The architecture **dpkg** is built for (i.e.
               the output of **--print-architecture**) is always part of that
               list.
    
           **--remove-architecture** _architecture_
               Remove _architecture_ from the list of architectures for which
               packages can be installed without using **--force-architecture**
               (since dpkg 1.16.2).  If the architecture is currently in use
               in the database then the operation will be refused, except if
               **--force-architecture** is specified.  The architecture **dpkg** is
               built for (i.e. the output of **--print-architecture**) can never
               be removed from that list.
    
           **--print-architecture**
               Print architecture of packages **dpkg** installs (for example,
               “i386”).
    
           **--print-foreign-architectures**
               Print a newline-separated list of the extra architectures **dpkg**
               is configured to allow packages to be installed for (since
               dpkg 1.16.2).
    
           **--assert-help**
               Give help about the **--assert-**_feature_ options (since dpkg
               1.21.0).
    
           **--assert-**_feature_
               Asserts that **dpkg** supports the requested feature.  Returns 0
               if the feature is fully supported, 1 if the feature is known
               but **dpkg** cannot provide support for it yet, and 2 if the
               feature is unknown.  The current list of assertable features
               is:
    
               **support-predepends**
                   Supports the **Pre-Depends** field (since dpkg 1.1.0).
    
               **working-epoch**
                   Supports epochs in version strings (since dpkg 1.4.0.7).
    
               **long-filenames**
                   Supports long filenames in deb(5) archives (since dpkg
                   1.4.1.17).
    
               **multi-conrep**
                   Supports multiple **Conflicts** and **Replaces**(since dpkg
                   1.4.1.19).
    
               **multi-arch**
                   Supports multi-arch fields and semantics (since dpkg
                   1.16.2).
    
               **versioned-provides**
                   Supports versioned **Provides**(since dpkg 1.17.11).
    
               **protected-field**
                   Supports the **Protected** field (since dpkg 1.20.1).
    
           **--validate-**_thing string_
               Validate that the _thing string_ has a correct syntax (since
               dpkg 1.18.16).  Returns 0 if the _string_ is valid, 1 if the
               _string_ is invalid but might be accepted in lax contexts, and 2
               if the _string_ is invalid.  The current list of validatable
               _thing_ s is:
    
               **pkgname**
                   Validates the given package name (since dpkg 1.18.16).
    
               **trigname**
                   Validates the given trigger name (since dpkg 1.18.16).
    
               **archname**
                   Validates the given architecture name (since dpkg
                   1.18.16).
    
               **version**
                   Validates the given version (since dpkg 1.18.16).
    
           **--compare-versions** _ver1 op ver2_
               Compare version numbers, where _op_ is a binary operator.  **dpkg**
               returns true (**0**) if the specified condition is satisfied, and
               false (**1**) 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: **< << <= = >= >> >**.
               The **< **and **> **operators are obsolete and should **not** be used, due
               to confusing semantics.  To illustrate: **0.1 < 0.1 **evaluates to
               true.
    
           **-?** , **--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.
    
               When used with **--robot** , the output will be the program version
               number in a dotted numerical format, with no newline.
    
           **dpkg-deb actions**
               See dpkg-deb(1) for more information about the following
               actions, and other actions and options not exposed by the **dpkg**
               front-end.
    
               **-b** , **--build** _directory_ [_archive_ |_directory_]
                   Build a deb package.
    
               **-c** , **--contents** _archive_
                   List contents of a deb package.
    
               **-e** , **--control** _archive_ [_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.
    
               **--ctrl-tarfile** _archive_
                   Output the control tar-file contained in a Debian package.
    
               **--fsys-tarfile** _archive_
                   Output 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, and other actions and options not exposed by the **dpkg**
               front-end.
    
               **-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
                   _/usr/local/var/lib/dpkg/available_.  Users of APT-based
                   frontends should use **apt show** _package-name_ instead.
    


## OPTIONS



           All options can be specified both on the command line and in the
           **dpkg** configuration file _/usr/local/etc/dpkg/dpkg.cfg_ or fragment
           files (with names matching this shell pattern '[0-9a-zA-Z_-]*') on
           the configuration directory _/usr/local/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 hyphens) 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.
    
           **-D** _octal_ , **--debug=**_octal_
               Switch debugging on.  _octal_ is formed by bitwise-ORing 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 for example 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** :
                 Allow automatic installs, upgrades or removals of packages
                 even when marked to be on “hold”.  **Note** : When these actions
                 are requested explicitly, the “hold” package selection state
                 always gets ignored.
    
               **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-protected** :
                 Remove, even if the package is considered protected (since
                 dpkg 1.20.1).  Protected packages contain mostly important
                 system boot infrastructure or are used for custom
                 system-local meta-packages.  Removing them might cause the
                 whole system to be unable to boot or lose required
                 functionality to operate, so use with caution.
    
               **remove-essential** :
                 Remove, even if the package is considered essential.
                 Essential packages contain mostly very basic Unix commands,
                 required for the packaging system, for the operation of the
                 system in general or during boot (although the latter should
                 be converted to protected packages instead).  Removing them
                 might cause the whole system to stop working, so use with
                 caution.
    
               **depends** :
                 Turn all dependency problems into warnings.  This affects
                 the **Pre-Depends** and **Depends** fields.
    
               **depends-version** :
                 Don't care about versions when checking dependencies.  This
                 affects the **Pre-Depends** and **Depends** fields.
    
               **breaks** :
                 Install, even if this would break another package (since
                 dpkg 1.14.6).  This affects the **Breaks** field.
    
               **conflicts** :
                 Install, even if it conflicts with another package.  This is
                 dangerous, for it will usually cause overwriting of some
                 files.  This affects the **Conflicts** field.
    
               **confmiss** :
                 Always install the missing conffile without prompting.  This
                 is dangerous, since it means not preserving a change
                 (removing) made to the file.
    
               **confnew** :
                 If a conffile has been modified and the version in the
                 package did change, 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 and the version in the
                 package did change, 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 and the version in the
                 package did change, always choose the default action without
                 prompting.  If there is no default action it will stop to
                 ask the user unless **--force-confnew** or **--force-confold** is
                 also 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 (since dpkg 1.15.8).  If any of
                 **--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.
    
               **statoverride-add** :
                 Overwrite an existing stat override when adding it (since
                 dpkg 1.19.5).
    
               **statoverride-remove** :
                 Ignore a missing stat override when removing it (since dpkg
                 1.19.5).
    
               **security-mac**(*):
                 Use platform-specific Mandatory Access Controls (MAC) based
                 security when installing files into the filesystem (since
                 dpkg 1.19.5).  On Linux systems the implementation uses
                 SELinux.
    
               **unsafe-io** :
                 Do not perform safe I/O operations when unpacking (since
                 dpkg 1.15.8.6).  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.
    
               **script-chrootless** :
                 Run maintainer scripts without chroot(2)ing into **instdir**
                 even if the package does not support this mode of operation
                 (since dpkg 1.18.5).
    
                 **Warning** : This can destroy your host system, use with extreme
                 care.
    
               **architecture** :
                 Process even packages with wrong or no architecture.
    
               **bad-version** :
                 Process even packages with wrong versions (since dpkg
                 1.16.1).
    
               **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).  This affects the **Pre-Depends** , **Depends**
               and **Breaks** fields.
    
           **--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
               **--record-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_
               Set the administrative directory to _directory_.  This directory
               contains many files that give information about status of
               installed or uninstalled packages, etc.  Defaults to
               « _/usr/local/var/lib/dpkg_ » if **DPKG_ADMINDIR** has not been set.
    
           **--instdir=**_dir_
               Set the 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_
               Set the root directory to **directory** , which sets the
               installation directory to « _dir_ » and the administrative
               directory to « _dir_**/usr/local/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 and architecture
               of the package is already installed.
    
               Since dpkg 1.21.10, the architecture is also taken into
               account, which makes it possible to cross-grade packages or
               install additional co-installable instances with the same
               version, but different architecture.
    
           **--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_ actions (since dpkg 1.15.4),
               and _add-architecture_ and _remove-architecture_ actions (since
               dpkg 1.17.19).  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.
    
               The invoke hooks are not executed when **--no-act** is specified,
               or when running as non-root without **--force-not-root**.
    
               **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 (since dpkg 1.15.8).
    
               **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, in particular when there is a more specific
               re-inclusion, 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.
    
               The filters are applied when unpacking the binary packages,
               and as such only have knowledge of the type of object
               currently being filtered (e.g. a normal file or a directory)
               and have not visibility of what objects will come next.
               Because these filters have side effects (in contrast to
               find(1) filters), excluding an exact pathname that happens to
               be a directory object like _/usr/share/doc_ will not have the
               desired result, and only that pathname will be excluded (which
               could be automatically reincluded if the code sees the need).
               Any subsequent files contained within that directory will fail
               to unpack.
    
               **Hint** : make sure the globs are not expanded by your shell.
    
           **--verify-format** _format-name_
               Sets the output format for the **--verify** command (since dpkg
               1.17.2).
    
               The only currently supported output format is **rpm** , which
               consists of a line for every path that failed any check.
               These lines have the following format:
    
                **missing**[**c**] _pathname_ [**(**_error-message_**)**]
                **?M5??????**[**c**] _pathname_
    
               The first 9 characters are used to report the checks result,
               either a literal **missing** when the file is not present or its
               metadata cannot be fetched, or one of the following special
               characters that report the result for each check:
    
               ‘**?** ’ Implies the check could not be done (lack of support, file
                   permissions, etc).
    
               ‘**.** ’ Implies the check passed.
    
               ‘ _A-Za-z0-9_ ’
                   Implies a specific check failed.  The following positions
                   and alphanumeric characters are currently supported:
    
                   1 ‘**?** ’
                       These checks are currently not supported, will always
                       be ‘**?** ’.
    
                   2 ‘**M** ’
                       The file mode check failed (since dpkg 1.21.0).
                       Because pathname metadata is currently not tracked,
                       this check can only be partially emulated via a very
                       simple heuristic for pathnames that have a known
                       digest, which implies they should be regular files,
                       where the check will fail if the pathname is not a
                       regular file on the filesystem.  This check will
                       currently never succeed as it does not have enough
                       information available.
    
                   3 ‘**5** ’
                       The digest check failed, which means the file contents
                       have changed.  This is only an integrity check and
                       should not be considered as any kind of security
                       verification.
    
                   4-9 ‘**?** ’
                       These checks are currently not supported, will always
                       be ‘**?** ’.
    
               The line is followed by a space and an attribute character.
               The following attribute character is supported:
    
               ‘**c** ’ The pathname is a conffile.
    
               Finally followed by another space and the pathname.
    
               In case the entry was of the **missing** type, and the file was
               not actually present on the filesystem, then the line is
               followed by a space and the error message enclosed within
               parenthesis.
    
           **--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.  Any possible newlines in
                   _extended-error-message_ will be converted to spaces before
                   output.
    
               **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**.
    
           **--status-logger** =_command_
               Send machine-readable package status and progress information
               to the shell _command_ 's standard input, to be run via “sh -c”
               (since dpkg 1.16.0).  This option can be specified multiple
               times.  The output format used is the same as in **--status-fd**.
    
               The status loggers are not executed when **--no-act** is
               specified, or when running as non-root without
               **--force-not-root**.
    
           **--log=**_filename_
               Log status change updates and actions to _filename_ , instead of
               the default _/usr/local/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 **startup** _type command_
                   For each dpkg invocation where _type_ is **archives**(with a
                   _command_ of **unpack** or **install**) or **packages**(with a _command_
                   of **configure** , **triggers-only** , **remove** or **purge**).
    
               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** ,
                   **configure** , **trigproc** , **disappear** , **remove** or **purge**.
    
               YYYY-MM-DD HH:MM:SS **conffile** _filename decision_
                   For conffile changes where _decision_ is either **install** or
                   **keep**.
    
           **--robot**
               Use a machine-readable output format.  This provides an
               interface for programs that need to parse the output of some
               of the commands that do not otherwise emit a machine-readable
               output format.  No localization will be used, and the output
               will be modified to make it easier to parse.
    
               The only currently supported command is **--version**.
    
           **--no-pager**
               Disables the use of any pager when showing information (since
               dpkg 1.19.2).
    
           **--no-debsig**
               Do not try to verify package signatures.
    
           **--no-triggers**
               Do not run any triggers in this run (since dpkg 1.14.17), but
               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**(since dpkg 1.14.17).
    


## EXIT STATUS



           **0** The requested action was successfully performed.  Or a check
               or assertion command returned true.
    
           **1** A check or assertion command returned false.
    
           **2** Fatal or unrecoverable error due to invalid command-line
               usage, or interactions with the system, such as accesses to
               the database, memory allocations, etc.
    


## ENVIRONMENT



       **External environment**
           **PATH**
               This variable is expected to be defined in the environment and
               point to the system paths where several required programs are
               to be found.  If it's not set or the programs are not found,
               **dpkg** will abort.
    
           **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.
    
           **SHELL**
               The program **dpkg** will execute when starting a new interactive
               shell, or when spawning a command via a shell.
    
           **PAGER**
           **DPKG_PAGER**
               The program **dpkg** will execute when running a pager, which will
               be executed with «**$SHELL -c** », for example when displaying the
               conffile differences.  If **SHELL** is not set, «**sh** » will be used
               instead.
    
               The **DPKG_PAGER** overrides the **PAGER** environment variable (since
               dpkg 1.19.2).  If none of the programs pointed by **DPKG_PAGER**
               or **PAGER** are present, the following programs will be tried in
               order (since dpkg 1.22.12): the default pager **less** , then **less** ,
               **more** , and finally **cat**.
    
           **DPKG_COLORS**
               Sets the color mode (since dpkg 1.18.5).  The currently
               accepted values are: **auto**(default), **always** and **never**.
    
           **DPKG_NLS**
               If set, it will be used to decide whether to activate Native
               Language Support, also known as internationalization (or i18n)
               support (since dpkg 1.22.7).  The accepted values are: **0** and **1**
               (default).
    
           **DPKG_DEBUG**
               Sets the debug mask (since dpkg 1.21.10) from an octal value.
               The currently accepted flags are described in the **--debug**
               option.
    
           **DPKG_FORCE**
               Sets the force flags (since dpkg 1.19.5).  When this variable
               is present, no built-in force defaults will be applied.  If
               the variable is present but empty, all force flags will be
               disabled.
    
           **DPKG_ADMINDIR**
               If set and the **--admindir** or **--root** options have not been
               specified, it will be used as the **dpkg** administrative
               directory (since dpkg 1.20.0).
    
           **DPKG_FRONTEND_LOCKED**
               Set by a package manager frontend to notify dpkg that it
               should not acquire the frontend lock (since dpkg 1.19.1).
    
           **DPKG_PATH_PASSWD**
               Sets the pathname for the system _passwd_ file.  This path is
               relative to the **--root** directory.  The default is _/etc/passwd_.
    
               Since dpkg 1.22.16.
    
           **DPKG_PATH_GROUP**
               Sets the pathname for the system _group_ file.  This path is
               relative to the **--root** directory.  The default is _/etc/group_.
    
               Since dpkg 1.22.16.
    
       **Internal environment**
           **LESS**
               Defined by **dpkg** to “**-FRSXMQ** ”, if not already set, when
               spawning a pager (since dpkg 1.19.2).  To change the default
               behavior, this variable can be preset to some other value
               including an empty string, or the **PAGER** or **DPKG_PAGER**
               variables can be set to disable specific options with «**-+** »,
               for example **DPKG_PAGER="less -+F"**.
    
           **DPKG_ROOT**
               Defined by **dpkg** on the maintainer script environment to
               indicate which installation to act on (since dpkg 1.18.5).
               The value is intended to be prepended to any path maintainer
               scripts operate on.  During normal operation, this variable is
               empty.  When installing packages into a different **instdir** ,
               **dpkg** normally invokes maintainer scripts using chroot(2) and
               leaves this variable empty, but if **--force-script-chrootless**
               is specified then the chroot(2) call is skipped and **instdir** is
               non-empty.
    
           **DPKG_ADMINDIR**
               Defined by **dpkg** on the maintainer script environment to
               indicate the **dpkg** administrative directory to use (since dpkg
               1.16.0).  This variable is always set to the current
               **--admindir** value.
    
           **DPKG_FORCE**
               Defined by **dpkg** on the subprocesses environment to all the
               currently enabled force option names separated by commas
               (since dpkg 1.19.5).
    
           **DPKG_SHELL_REASON**
               Defined by **dpkg** on the shell spawned on the conffile prompt to
               examine the situation (since dpkg 1.15.6).  Current valid
               value: **conffile-prompt**.
    
           **DPKG_CONFFILE_OLD**
               Defined by **dpkg** on the shell spawned on the conffile prompt to
               examine the situation (since dpkg 1.15.6).  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 (since dpkg 1.15.6).  Contains the path
               to the new conffile.
    
           **DPKG_HOOK_ACTION**
               Defined by **dpkg** on the shell spawned when executing a hook
               action (since dpkg 1.15.4).  Contains the current **dpkg** action.
    
           **DPKG_RUNNING_VERSION**
               Defined by **dpkg** on the maintainer script environment to the
               version of the currently running **dpkg** instance (since dpkg
               1.14.17).
    
           **DPKG_MAINTSCRIPT_PACKAGE**
               Defined by **dpkg** on the maintainer script environment to the
               (non-arch-qualified) package name being handled (since dpkg
               1.14.17).
    
           **DPKG_MAINTSCRIPT_PACKAGE_REFCOUNT**
               Defined by **dpkg** on the maintainer script environment to the
               package reference count, i.e. the number of package instances
               with a state greater than **not-installed**(since dpkg 1.17.2).
    
           **DPKG_MAINTSCRIPT_ARCH**
               Defined by **dpkg** on the maintainer script environment to the
               architecture the package got built for (since dpkg 1.15.4).
    
           **DPKG_MAINTSCRIPT_NAME**
               Defined by **dpkg** on the maintainer script environment to the
               name of the script running, one of **preinst** , **postinst** , **prerm** or
               **postrm**(since dpkg 1.15.7).
    
           **DPKG_MAINTSCRIPT_DEBUG**
               Defined by **dpkg** on the maintainer script environment to a
               value (‘**0** ’ or ‘**1** ’) noting whether debugging has been requested
               (with the **--debug** option) for the maintainer scripts (since
               dpkg 1.18.4).
    


## FILES



           _/usr/local/etc/dpkg/dpkg.cfg.d/[0-9a-zA-Z_-]*_
               Configuration fragment files (since dpkg 1.15.4).
    
           _/usr/local/etc/dpkg/dpkg.cfg_
               Configuration file with default options.
    
           _/usr/local/var/log/dpkg.log_
               Default log file (see _/usr/local/etc/dpkg/dpkg.cfg_ 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.
    
           _/usr/local/var/lib/dpkg/available_
               List of available packages.
    
           _/usr/local/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 _/usr/local/var/backups_.
               It can be useful if it's lost or corrupted due to filesystems
               troubles.
    
           The format and contents of a binary package are described in
           deb(5).
    
       **Filesystem filenames**
           During unpacking and configuration **dpkg** uses various filenames for
           backup and rollback purposes.  The following is a simplified
           explanation of how these filenames get used during package
           installation.
    
           _*.dpkg-new_
               During unpack, **dpkg** extracts new filesystem objects into
               _pathname_**.dpkg-new**(except for existing directories or symlinks
               to directories which get skipped), once that is done and after
               having performed backups of the old objects, the objects get
               renamed to _pathname_.
    
           _*.dpkg-tmp_
               During unpack, **dpkg** makes backups of the old filesystem
               objects into _pathname_**.dpkg-tmp** after extracting the new
               objects.  These backups are performed as either a rename for
               directories (but only if they switch file type), a new symlink
               copy for symlinks, or a hard link for any other filesystem
               object, except for conffiles which get no backups because they
               are processed at a later stage.
    
               In case of needing to rollback, these backups get used to
               restore the previous contents of the objects.  These get
               removed automatically after the installation is complete.
    
           _*.dpkg-old_
               During configuration, when installing a new version, **dpkg** can
               make a backup of the previous modified conffile into
               _pathname_**.dpkg-old**.
    
           _*.dpkg-dist_
               During configuration, when keeping the old version, **dpkg** can
               make a backup of the new unmodified conffile into
               _pathname_**.dpkg-dist**.
    


## SECURITY



           Any operation that needs write access to the database or the
           filesystem is considered a privileged operation that might allow
           root escalation.  These operations must never be delegated to an
           untrusted user or be done on untrusted packages, as that might
           allow root access to the system.
    
           Some operations (such as package verification) might need root
           privileges to be able to access files on the filesystem that would
           otherwise be inaccessible due to restricted permissions, but
           should otherwise work normally and produce appropriate messages in
           those cases.
    
           Query operations should never require root, and delegating their
           execution to unprivileged users via some gain-root command can
           have security implications (such as privilege escalation), for
           example when a pager is automatically invoked by the tool.
    
           See also the **SECURITY** section of the dpkg-deb(1) and dpkg-split(1)
           manual pages.
    


## BUGS



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


## EXAMPLES



           To list installed packages related to the editor **vi**(1) (note that
           **dpkg-query** does not load the _available_ file anymore by default,
           and the **dpkg-query --load-avail** option should be used instead for
           that):
    
            dpkg -l '*vi*'
    
           To see the entries in _/usr/local/var/lib/dpkg/available_ of two
           packages:
    
            dpkg --print-avail vim neovim | less
    
           To search the listing of packages yourself:
    
            dpkg --print-avail | less
    
           To remove an installed neovim package:
    
            dpkg -r neovim
    
           To install a package, you first need to find it in an archive or
           media disc.  When using an archive based on a pool structure,
           knowing the archive area and the name of the package is enough to
           infer the pathname:
    
            dpkg -i /media/bdrom/pool/main/v/vim/vim_9.0.2018-1_amd64.deb
    
           To make a local copy of the package selection states:
    
            dpkg --get-selections >myselections
    
           You might transfer this file to another computer, and after having
           updated the _available_ file there with your package manager
           frontend of choice (see
           <https://wiki.debian.org/Teams/Dpkg/FAQ#set-selections> for more
           details), for example:
    
            apt-cache dumpavail | dpkg --merge-avail
    
           you can install it 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 **debsig-verify**.
    


* * *