Provided by: dpkg_1.18.4ubuntu1_i386 bug


       dpkg - package manager for Debian


       dpkg [option...] action


       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.


       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.


       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
              The package is not installed on your system.

              Only the configuration files of the package exist on the system.

              The  installation  of  the  package  has  been  started, but not
              completed for some reason.

              The package is unpacked, but not configured.

              The package is unpacked and configuration has been started,  but
              not yet completed for some reason.

              The package awaits trigger processing by another package.

              The package has been triggered.

              The package is correctly unpacked and configured.

   Package selection states
              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.

              The package is selected for  deinstallation  (i.e.  we  want  to
              remove all files, except configuration files).

       purge  The  package  is  selected  to be purged (i.e. we want to remove
              everything from system directories, even configuration files).

   Package flags
              A  package  marked  reinst-required  is  broken   and   requires
              reinstallation.  These packages cannot be removed, unless forced
              with option --force-remove-reinstreq.


       -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

       --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, 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  -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.  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

              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.

       --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.

              Now obsolete and a  no-op  as  dpkg  will  automatically  forget
              uninstalled unavailable packages (since dpkg 1.15.4).

              Erase   the   existing   information  about  what  packages  are

       -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.

       --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  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.

              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.

              Searches for packages selected for installation, but  which  for
              some reason still haven't been installed.

              Print  a  single  package  which  is  the  target of one or more
              relevant pre-dependencies and has  itself  no  unsatisfied  pre-

              If  such  a  package  is  present,  output it as a Packages file
              entry, which can be massaged as appropriate.

              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  of  packages  dpkg  installs  (for  example,

              Print  a  newline-separated list of the extra architectures dpkg
              is configured to allow packages to be installed for (since  dpkg

              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:

                     Supports the Pre-Depends field (since dpkg 1.1.0).

                     Supports epochs in version strings (since dpkg

                     Supports long filenames in deb(5)  archives  (since  dpkg

                     Supports  multiple  Conflicts  and  Replaces  (since dpkg

                     Supports multi-arch  fields  and  semantics  (since  dpkg

                     Supports versioned Provides (since dpkg 1.17.11).

       --compare-versions ver1 op ver2
              Compare  version  numbers,  where  op is a binary operator. dpkg
              returns success (zero result)  if  the  specified  condition  is
              satisfied, and failure (nonzero result) otherwise. There are two
              groups of operators, which differ in how  they  treat  an  empty
              ver1  or  ver2. These treat an empty version as earlier than any
              version: lt le eq ne ge gt. These  treat  an  empty  version  as
              later  than  any  version:  lt-nl  le-nl  ge-nl gt-nl. These are
              provided only for compatibility with control file syntax:  <  <<
              <=  = >= >> >. 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.

              Give help about the --force-thing options.

       -Dh, --debug=help
              Give help about debugging options.

              Display dpkg version information.

       dpkg-deb actions
              See   dpkg-deb(1)  for  more  information  about  the  following

              -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
              -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

              -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.


       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 #).

              Change after how many errors dpkg will abort. The default is 50.

       -B, --auto-deconfigure
              When a package is removed, there is a possibility  that  another
              installed  package  depended  on the removed package. Specifying
              this option will cause automatic deconfiguration of the  package
              which depended on the removed package.

       -Doctal, --debug=octal
              Switch  debugging  on. octal is formed by bitwise-orring desired
              values together from the list below (note that these values  may
              change  in  future  releases). -Dh or --debug=help display these
              debugging values.

                  Number   Description
                       1   Generally helpful progress information
                       2   Invocation and status of maintainer scripts
                      10   Output for each file processed
                     100   Lots of output for each file processed
                      20   Output for each configuration file
                     200   Lots of output for each configuration file
                      40   Dependencies and conflicts
                     400   Lots of dependencies/conflicts output
                   10000   Trigger activation and processing
                   20000   Lots of output regarding triggers
                   40000   Silly amounts of output regarding triggers
                    1000   Lots of drivel about e.g. the dpkg/info dir
                    2000   Insane amounts of drivel

       --no-force-things, --refuse-things
              Force or refuse (no-force and refuse mean the same thing) to  do
              some  things.  things  is  a  comma  separated  list  of  things
              specified below.  --force-help  displays  a  message  describing
              them.  Things marked with (*) are forced by default.

              Warning: These options are mostly intended to be used by experts
              only. Using them without fully understanding their  effects  may
              break your whole system.

              all: Turns on (or off) all force options.

              downgrade(*):  Install a package, even if newer version of it is
              already installed.

              Warning: At present dpkg does not do any dependency checking  on
              downgrades  and  therefore  will  not  warn you if the downgrade
              breaks the dependency of  some  other  package.  This  can  have
              serious  side  effects,  downgrading essential system components
              can even make your whole system unusable. Use with care.

              configure-any: Configure  also  any  unpacked  but  unconfigured
              packages on which the current package depends.

              hold: Process packages even when marked “hold”.

              remove-reinstreq:  Remove  a  package,  even  if it's broken and
              marked to require reinstallation. This may, for  example,  cause
              parts of the package to remain on the system, which will then be
              forgotten by dpkg.

              remove-essential: Remove, even  if  the  package  is  considered
              essential.  Essential  packages  contain  mostly very basic Unix
              commands. Removing them might cause the  whole  system  to  stop
              working, so use with caution.

              depends: Turn all dependency problems into warnings.

              depends-version:   Don't   care  about  versions  when  checking

              breaks: Install, even if this would break another package (since
              dpkg 1.14.6).

              conflicts:  Install,  even if it conflicts with another package.
              This is dangerous, for it will usually cause overwriting of some

              confmiss:  If  a  conffile  is  missing  and  the version in the
              package did change, 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

              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-confmiss,    --force-confnew,    --force-confold,     or
              --force-confdef  is  also  given,  it will be used to decide the
              final action.

              overwrite: Overwrite one package's file with another's file.

              overwrite-dir: Overwrite one package's directory with  another's

              overwrite-diverted: Overwrite a diverted file with an undiverted

              unsafe-io: Do not perform safe  I/O  operations  when  unpacking
              (since  dpkg   Currently this implies not performing
              file system syncs before file renames, which is known  to  cause
              substantial   performance  degradation  on  some  file  systems,
              unfortunately the ones that require the safe I/O  on  the  first
              place  due  to  their  unreliable  behaviour causing zero-length
              files on abrupt system crashes.

              Note: For ext4, the main offender, consider  using  instead  the
              mount  option  nodelalloc,  which  will fix both the performance
              degradation and the data safety issues, the latter by making the
              file  system  not  produce  zero-length  files  on abrupt system
              crashes with any software not doing syncs before atomic renames.

              Warning: Using this option might improve performance at the cost
              of losing data, use with care.

              architecture:   Process   even   packages   with   wrong  or  no

              bad-version: Process even packages with  wrong  versions  (since
              dpkg 1.16.1).

              bad-path:  PATH  is  missing important programs, so problems are

              not-root: Try to (de)install things even when not root.

              bad-verify: Install a package  even  if  it  fails  authenticity

              Ignore  dependency-checking  for  specified  packages (actually,
              checking is performed, but only  warnings  about  conflicts  are
              given, nothing else).

       --no-act, --dry-run, --simulate
              Do  everything which is supposed to be done, but don't write any
              changes. This  is  used  to  see  what  would  happen  with  the
              specified action, without actually modifying anything.

              Be  sure  to  give  --no-act before the action-parameter, or you
              might end up with undesirable results. (e.g.  dpkg  --purge  foo
              --no-act  will  first  purge  package  foo and then try to purge
              package --no-act,  even  though  you  probably  expected  it  to
              actually do nothing)

       -R, --recursive
              Recursively  handle  all  regular  files  matching pattern *.deb
              found at specified directories and all  of  its  subdirectories.
              This  can  be  used with -i, -A, --install, --unpack and --avail

       -G     Don't install a package if a newer version of the  same  package
              is already installed. This is an alias of --refuse-downgrade.

              Change  default  administrative  directory,  which contains many
              files  that  give  information  about  status  of  installed  or
              uninstalled packages, etc.  (Defaults to /var/lib/dpkg)

              Change  default  installation  directory  which  refers  to  the
              directory where packages are to be installed.  instdir  is  also
              the  directory  passed  to  chroot(2)  before  running package's
              installation scripts, which means that the scripts  see  instdir
              as a root directory.  (Defaults to /)

              Changing   root   changes   instdir   to  dir  and  admindir  to

       -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.

              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.

              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:


              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

       --verify-format format-name
              Sets the output format for  the  --verify  command  (since  dpkg

              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.

              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 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; and  ‘YYYY-MM-DD  HH:MM:SS
              conffile  filename decision’ for conffile changes where decision
              is either install or keep.

              Do not try to verify package signatures.

              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.

              Cancels a previous --no-triggers (since dpkg 1.14.17).


   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.

       PAGER  The program dpkg will execute when displaying the conffiles.

       SHELL  The  program  dpkg  will execute when starting a new interactive

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

   Internal environment
              Defined  by  dpkg on the shell spawned on the conffile prompt to
              examine the situation (since dpkg 1.15.6).  Current valid value:

              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.

              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.

              Defined  by  dpkg  on  the  shell  spawned when executing a hook
              action (since dpkg 1.15.4).  Contains the current dpkg action.

              Defined by dpkg on the  maintainer  script  environment  to  the
              version  of  the  currently  running  dpkg  instance (since dpkg

              Defined by dpkg on the  maintainer  script  environment  to  the
              (non-arch-qualified)  package  name  being  handled  (since dpkg

              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).

              Defined by dpkg on the  maintainer  script  environment  to  the
              architecture the package got built for (since dpkg 1.15.4).

              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).

              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


              Configuration fragment files (since dpkg 1.15.4).

              Configuration file with default options.

              Default log file (see /etc/dpkg/dpkg.cfg(5) and option --log).

       The other files listed below are  in  their  default  directories,  see
       option --admindir to see how to change locations of these files.

              List of available packages.

              Statuses  of  available packages. This file contains information
              about whether a package is marked for removing or  not,  whether
              it  is  installed  or  not,  etc.  See section INFORMATION ABOUT
              PACKAGES for more info.

              The status file is backed up daily in /var/backups.  It  can  be
              useful if it's lost or corrupted due to filesystems troubles.

       The  following files are components of a binary package. See deb(5) for
       more information about them:


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


       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 for more details),
       for example:
            apt-cache dumpavail | dpkg --merge-avail
       or with dpkg 1.17.6 and earlier:
            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  can  be  gained  by  installing  any  of  the
       following packages: apt, aptitude and debsums.


       aptitude(1), apt(1), dselect(1), dpkg-deb(1), dpkg-query(1), deb(5),
       deb-control(5), dpkg.cfg(5), and dpkg-reconfigure(8).


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