NAME
    CPAN - query, download and build perl modules from CPAN sites

SYNOPSIS
    Interactive mode:

      perl -MCPAN -e shell;


    Batch mode:

      use CPAN;

      autobundle, bundle, bundles, expand, install, make, test


ALPHA ALERT
    The interface of this package is not yet stable. Parts of it may
    still change. This is especially true for the programming
    interface. The interactive "shell" interface is already rather
    well established.

DESCRIPTION
    The CPAN module is designed to automate the building and
    installing of perl modules and extensions including the
    searching and fetching from the net.

    Modules are fetched from one or more of the mirrored CPAN
    (Comprehensive Perl Archive Network) sites and unpacked in a
    dedicated directory.

    The CPAN module also supports the concept of named and versioned
    'bundles' of modules. Bundles simplify the handling of sets of
    related modules. See BUNDLES below.

    The package contains a session manager and a cache manager.
    There is no status retained between sessions. The session
    manager keeps track of what has been fetched, built and
    installed in the current session. The cache manager keeps track
    of the disk space occupied by the make processes and deletes
    excess space in a simple FIFO style.

  Interactive Mode

    The interactive mode is entered by running

        perl -MCPAN -e shell


    which puts you into a readline interface. You will have most fun
    if you install Term::ReadKey and Term::ReadLine to enjoy both
    history and completion.

    Once you are on the command line, type 'h' and the rest should
    be self-explanatory.

  CPAN::Shell

    The commands that are available in the shell interface are
    methods in the package CPAN::Shell. If you enter the shell
    command, all your input is split on whitespace, the first word
    is being interpreted as the method to be called and the rest of
    the words are treated as arguments to this method.

    If you do not enter the shell, most of the available shell
    commands are both available as methods (`CPAN::Shell-
    >install(...)') and as functions in the calling package
    (`install(...)').

  Cache Manager

    Currently the cache manager only keeps track of the build
    directory ($CPAN::Config->{build_dir}). It is a simple FIFO
    mechanism that deletes complete directories below build_dir as
    soon as the size of all directories there gets bigger than
    $CPAN::Config->{build_cache} (in MB).

    There is another directory ($CPAN::Config->{keep_source_where})
    where the original distribution files are kept. This directory
    is not covered by the cache manager and must be controlled by
    the user. If you choose to have the same directory as build_dir
    and as keep_source_where directory, then your sources will be
    deleted with the same fifo mechanism.

  Bundles

    A bundle is just a perl module in the namespace Bundle:: that
    does not define any functions or methods. It usually only
    contains documentation.

    It starts like a perl module with a package declaration and a
    $VERSION variable. After that the pod section looks like any
    other pod with the only difference, that one pod section exists
    starting with (verbatim):

    	=head1 CONTENTS


    In this pod section each line obeys the format

            Module_Name [Version_String] [- optional text]


    The only required part is the first field, the name of a module
    (eg. Foo::Bar, ie. *not* the name of the distribution file). The
    rest of the line is optional. The comment part is delimited by a
    dash just as in the man page header.

    The distribution of a bundle should follow the same convention
    as other distributions. The bundle() function in the CPAN module
    simply parses the module that defines the bundle and returns the
    module names that are listed in the described CONTENTS section.

    Bundles are treated specially in the CPAN package. If you say
    'install Bundle::Tkkit' (assuming such a bundle exists), CPAN
    will install all the modules in the CONTENTS section of the pod.
    You can install your own Bundles locally by placing a conformant
    Bundle file somewhere into your @INC path. The autobundle()
    command does that for you by including all currently installed
    in a snapshot bundle file.

  autobundle

    autobundle() writes a bundle file into the directory
    $CPAN::Config->{cpan_home}/Bundle directory. The file contains a
    list of all modules that are both available from CPAN and
    currently installed within @INC. The name of the bundle file is
    based on the current date and a counter.

  Pragma: force

    Normally CPAN keeps track of what it has done within the current
    session and doesn't try to build a package a second time
    regardless if it succeeded or not. The force command takes as
    first argument the method to invoke (currently: make, test, or
    install) and executes the command from scratch.

    Example:

        cpan> install OpenGL 
        OpenGL up-to-date.
        cpan> force install OpenGL 
        Running make
        OpenGL-0.4/
        OpenGL-0.4/COPYRIGHT
        [...]


CONFIGURATION
    When the CPAN module is installed a site wide configuration file
    is created as CPAN/Config.pm. The default values defined there
    can be overridden in another configuration file:
    CPAN/MyConfig.pm. You can store this file in
    $HOME/.cpan/CPAN/MyConfig.pm if you want, because $HOME/.cpan is
    added to the search path of the CPAN module before the use() or
    require() statements.

    Currently the following keys in the hash reference $CPAN::Config
    are defined:

      build_cache       size of cache for directories to build modules
      build_dir         locally accessible directory to build modules
      cache_expire      after how many days refetch index files
      cpan_home         local directory reserved for this package
      gzip		    location of external program gzip
      inhibit-startup-message
                        if true, does not print the startup message
      keep_source       keep the source in a local directory?
      keep_source_where where keep the source (if we do)
      make              location of external program make
      make_arg	    arguments that should always be passed to 'make'
      make_install_arg  same as make_arg for 'make install'
      makepl_arg	    arguments passed to 'perl Makefile.PL'
      more              location of external program more (or any pager)
      tar               location of external program tar
      unzip             location of external program unzip
      urllist	    arrayref to nearby CPAN sites (or equivalent locations)


SECURITY
    There's no security layer in the alpha version of CPAN.pm.
    CPAN.pm helps you to install foreign, unmasked, unsigned code on
    your machine. It's not different than when you do that on your
    own, but you should be warned now.

EXPORT
    Most functions in package CPAN are exported per default. The
    reason for this is that the primary use is intended for the
    cpan-shell or for one-liners.

Debugging
    The debugging of this module is a pretty difficult task, because
    we have interferences of the software producing the indices on
    CPAN, of the mirroring process, of improper packaging, of
    improper configuration and of bugs within CPAN.pm.

    In interactive mode you can try "o debug" which will list
    options for debugging the various parts of the package. The
    output may not be very useful for you as it's just a byproduct
    of my own testing, but if you have an idea which part of the
    package may have a bug, it's certainly worth to give it a try
    and send me more specific output. You should know that "o debug"
    has built-in completion support.

  Prerequisites

    If you have a local mirror of CPAN and can access all files with
    "file:" URLs, then you only need perl5.003 to run this module.
    Otherwise you need Net::FTP intalled. LWP may be required for
    non-UNIX systems.

    This module presumes that all packages on CPAN

    * Declare their $VERSION variable in an easy to parse manner. This
      prerequisite can hardly be relaxed because it consumes by far
      too much memory to load all packages into a single program
      just to determine the $VERSION variable . Currently all
      programs that are dealing with VERSION use something like this
      (requires MakeMaker-5.38, but don't bother if you don't have
      it):

          perl -MExtUtils::MakeMaker -le \
              'print MM->parse_version($ARGV[0])' filename


      If you are author of a package and wonder if your VERSION can
      be parsed, please try the above method.

    * Come as compressed or gzipped tarfiles or as zip files (well we
      try to handle a bit more, but without much enthusiasm).


AUTHOR
    Andreas König <a.koenig@mind.de>

SEE ALSO
    perl(1)

