ghc-pkg(1)						      General Commands Manual							ghc-pkg(1)

NAME

       ghc-pkg - GHC Haskell Cabal package manager

SYNOPSIS

       ghc-pkg action [OPTION]...

DESCRIPTION

       A  package is a library of Haskell modules known to the compiler.  The ghc-pkg tool allows adding or removing them from a package database.
       By default, the system-wide package database is modified, but alternatively the user's local package database or another specified file can
       be used.

       To  make  a  package available for ghc, ghc-pkg can be used to register it.  Unregistering it removes it from the database.  Also, packages
       can be hidden, to make ghc ignore the package by default, without uninstalling it.  Exposing a package makes a  hidden  package	available.
       Additionally, ghc-pkg has various commands to query the package database.

       Where a package name is required, the package can be named in full including the version number (e.g.  network-1.0), or without the version
       number. Naming a package without the version number matches all versions of the package; the specified action will be applied  to  all  the
       matching  packages. A package specifier that matches all version of the package can also be written pkg-*, to make it clearer that multiple
       packages are being matched.

ACTIONS

       register filename|-
	      Register the package using the specified installed package description.

       update filename|-
	      Register the package, overwriting any other package with the same name.

       unregister pkg-id
	      Unregister the specified package.

       expose pkg-id
	      Expose the specified package.

       hide pkg-id
	      Hide the specified package

       list [pkg]...
	      List registered packages in the global database, and also the user database if --user is given. If a package name is given  all  the
	      registered versions will be listed in ascending order.  Accepts the --simple-output flag.

       dot    Generate a graph of the package dependencies in a form suitable for input for the graphviz tools.  For example, to generate a PDF of
	      the dependency graph:
		  dot  tred  dot -Tpdf >pkgs.pdf

       find-module module
	      List registered packages exposing module module in the global database, and also the user database if --user is given. All the  reg-
	      istered versions will be listed in ascending order.  Accepts the --simple-output flag.

       latest pkg-id
	      Prints the highest registered version of a package.

       check  Check the consistency of package dependencies and list broken packages.  Accepts the --simple-output flag.

       describe pkg
	      Give  the  registered description for the specified package. The description is returned in precisely the syntax required by ghc-pkg
	      register.

       field pkg field
	      Extract the specified field of the package description for the specified package.  Accepts comma-separated multiple fields.

       dump   Dump the registered description for every package. This is like ghc-pkg describe '*', expect that it is intended to be used by tools
	      that parse the results, rather than humans.

       recache
	      Regenerate  the  package database cache.	This command should only be necessary if you added a package to the database by dropping a
	      file into the database directory manyally.  By default, the global DB is recached; to recache a different DB use --user  or  --pack-
	      age-conf as appropriate.

OPTIONS

       When  asked  to	modify	a  database  (register, unregister, update, hide, expose, and also check), ghc-pkg modifies the global database by
       default.  Specifying --user causes it to act on the user database, or --package-conf can be used to act on another database entirely.  When
       multiple of these options are given, the rightmost one is used as the database to act upon.

       Commands  that  query  the  package  database  (list, latest, describe, field)  operate	on  the  list  of databases specified by the flags
       --user, --global, and --package-conf.  If none of these flags are given, the default is --global --user.

       --user Use the current user's package database.

       --global
	      Use the global package database.

       -f FILE, --package-conf=FILE
	      Use the specified package config file.

       --global-conf=FILE
	      Location of the global package config.

       --force
	      Ignore missing dependencies, directories, and libraries.

       --force-files
	      Ignore missing directories and libraries only.

       -g, --auto-ghc-libs
	      Automatically build libs for GHCi (with register).

       -?, --help
	      Display a help message and exit.

       -V, --version
	      Output version information and exit.

       --simple-output
	      Print output in easy-to-parse format for some commands.

       --names-only
	      Only print package names, not versions; can only be used with list --simple-output.

       --ignore-case
	      Ignore case for substring matching.

ENVIRONMENT VARIABLES

       GHC_PACKAGE_PATH
	      The GHC_PACKAGE_PATH environment variable may be set to a :-separated list of files containing package databases. This list of pack-
	      age  databases  is used by ghc and ghc-pkg, with earlier databases in the list overriding later ones. This order was chosen to match
	      the behaviour of the PATH environment variable; think of it as a list of package databases that are searched left-to-right for pack-
	      ages.

	      If  GHC_PACKAGE_PATH  ends  in  a separator, then the default user and system package databases are appended, in that order. e.g. to
	      augment the usual set of packages with a database of your own, you could say:

		   export GHC_PACKAGE_PATH=$HOME/.my-ghc-packages.conf:

	      To check whether your GHC_PACKAGE_PATH setting is doing the right thing, ghc-pkg list will list all the databases  in  use,  in  the
	      reverse order they are searched.

FILES

       Both  of these locations are changed for Debian.  Upstream still keeps these under /usr.  Some programs may refer to that, but look in /var
       instead.

       /var/lib/ghc/package.conf
	      Global package.conf file.

       /var/lib/ghc/package.conf.d/
	      Directory for library specific package.conf files.  These are added to the global registry.

SEE ALSO

       ghc(1), runghc(1), hugs(1).

AUTHOR

       This manual page was written by Kari Pahula <kaol@debian.org>, for the Debian project (and may be used by others).

								    2010-01-27								ghc-pkg(1)