Provided by: dpkg_1.18.4ubuntu1.7_amd64 bug

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).

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

ACTIONS

       -i, --install package-file...
              Install the package. If --recursive or -R option  is  specified,  package-file  must  refer  to  a
              directory instead.

              Installation consists of the following steps:

              1. Extract the control files of the new package.

              2. If another version of the same package was installed before the new installation, execute prerm
              script of the old package.

              3. Run preinst script, if provided by the package.

              4. Unpack the new files, and at the same time back up the old files, so  that  if  something  goes
              wrong, they can be restored.

              5.  If  another version of the same package was installed before the new installation, execute the
              postrm script of the old package. Note that this script is executed after the  preinst  script  of
              the new package, because new files are written at the same time old files are removed.

              6. Configure the package. See --configure for detailed information about how this is done.

       --unpack package-file...
              Unpack the package, but don't configure it. If --recursive or -R option is specified, package-file
              must refer to a directory instead.

       --configure package...|-a|--pending
              Configure a package which has been unpacked but not yet configured.  If -a or --pending  is  given
              instead of package, all unpacked but unconfigured packages are configured.

              To  reconfigure  a  package which has already been configured, try the dpkg-reconfigure(8) command
              instead.

              Configuring consists of the following steps:

              1. Unpack the conffiles, and at the same time back up the old  conffiles,  so  that  they  can  be
              restored if something goes wrong.

              2. Run postinst script, if provided by the package.

       --triggers-only package...|-a|--pending
              Processes only triggers (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 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.

       --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).

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

       -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-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.

       --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.

              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).

       --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.

       --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-orring desired values together from the list below
              (note  that  these  values  may  change  in  future  releases).  -Dh or --debug=help display these
              debugging values.

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

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

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

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

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

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

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

              hold: Process packages even when marked “hold”.

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

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

              depends: Turn all dependency problems into warnings.

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

              breaks: Install, even if this would break another package (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 files.

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

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

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

              overwrite-diverted: Overwrite a diverted file with an undiverted version.

              unsafe-io: Do not perform safe I/O operations when unpacking  (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.

              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).

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

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

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

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

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

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

       --root=dir
              Changing root changes instdir to dir and admindir to dir/var/lib/dpkg.

       -O, --selected-only
              Only process the packages that are selected for installation. The  actual  marking  is  done  with
              dselect  or  by dpkg, when it handles packages. For example, when a package is removed, it will be
              marked selected for deinstallation.

       -E, --skip-same-version
              Don't install the package if the same version of the package is already installed.

       --pre-invoke=command
       --post-invoke=command
              Set an invoke hook command to be run via “sh -c” before or after the  dpkg  run  for  the  unpack,
              configure,  install,  triggers-only,  remove, 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.

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

       --no-debsig
              Do not try to verify package signatures.

       --no-triggers
              Do not run any triggers in this run (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).

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.

       PAGER  The program dpkg will execute when displaying the conffiles.

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

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

       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
       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(5) and option --log).

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

       /var/lib/dpkg/available
              List of available packages.

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

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

       The following files are components of a binary package. See deb(5) for more information about them:
              control
              conffiles
              preinst
              postinst
              prerm
              postrm
              triggers

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.