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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 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) 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 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 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).

       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.

       --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 (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 /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

       -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  /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.

       -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.

              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 /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-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).

       --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 things 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.

       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 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.

              -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 fragment files (with names matching this shell  pattern  '[0-9a-zA-Z_-]*')  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 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.

       -Doctal, --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 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.  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 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 (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 «/var/lib/dpkg».

       --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/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, purge, add-architecture  and  remove-architecture  dpkg
              actions  (since dpkg 1.15.4; 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. 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, 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.  The lines start with 9 characters to report each specific check result, a ‘?’
              implies the check could not be done (lack of support, file  permissions,  etc),  ‘.’  implies  the
              check  passed,  and  an  alphanumeric  character  implies  a  specific  check  failed;  the md5sum
              verification failure (the file contents  have  changed)  is  denoted  with  a  ‘5’  on  the  third
              character.   The  line  is  followed  by  a  space  and  an attribute character (currently ‘c’ for
              conffiles), another space and the pathname.

       --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.

       --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 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.

       --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, 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).

       DPKG_COLORS
              Sets  the  color  mode  (since  dpkg  1.18.5).  The currently accepted values are: auto (default),
              always and never.

       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_FRONTEND_LOCKED
              Set  by  a  package  manager  frontend to notify dpkg that it should not acquire the frontend lock
              (since dpkg 1.19.1).

   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

       /etc/dpkg/dpkg.cfg.d/[0-9a-zA-Z_-]*
              Configuration fragment files (since dpkg 1.15.4).

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

       /var/log/dpkg.log
              Default log file (see /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.

       /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 format and contents of a binary package are described in deb(5).

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 /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 /media/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 after having updated the available file there with
       your package manager frontend of choice (see https://wiki.debian.org/Teams/Dpkg/FAQ  for  more  details),
       for example:
            apt-cache dumpavail | dpkg --merge-avail
       or with dpkg 1.17.6 and earlier:
            avail=`mktemp`
            apt-cache dumpavail >"$avail"
            dpkg --merge-avail "$avail"
            rm "$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
       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).

AUTHORS

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