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NAME

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

SYNOPSIS

       Interactive mode:

         perl -MCPAN -e shell


       --or--
         cpan

       Basic commands:

         # Modules:

         cpan> install Acme::Meta                       # in the shell

         CPAN::Shell->install("Acme::Meta");            # in perl

         # Distributions:

         cpan> install NWCLARK/Acme-Meta-0.02.tar.gz    # in the shell

         CPAN::Shell->
           install("NWCLARK/Acme-Meta-0.02.tar.gz");    # in perl

         # module objects:

         $mo = CPAN::Shell->expandany($mod);
         $mo = CPAN::Shell->expand("Module",$mod);      # same thing

         # distribution objects:

         $do = CPAN::Shell->expand("Module",$mod)->distribution;
         $do = CPAN::Shell->expandany($distro);         # same thing
         $do = CPAN::Shell->expand("Distribution",
                                   $distro);            # same thing

DESCRIPTION

       The CPAN module automates or at least simplifies the make and install of perl modules and extensions. It
       includes some primitive searching capabilities and knows how to use LWP, HTTP::Tiny, Net::FTP and certain
       external download clients to fetch distributions from the net.

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

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

       The package contains a session manager and a cache manager. 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 using a simple FIFO mechanism.

       All methods provided are accessible in a programmer style and in an interactive shell style.

   CPAN::shell([$prompt, $command]) Starting Interactive Mode
       Enter interactive mode by running

           perl -MCPAN -e shell

       or

           cpan

       which puts you into a readline interface. If "Term::ReadKey" and either of "Term::ReadLine::Perl" or
       "Term::ReadLine::Gnu" are installed, history and command completion are supported.

       Once at the command line, type "h" for one-page help screen; the rest should be self-explanatory.

       The function call "shell" takes two optional arguments: one the prompt, the second the default initial
       command line (the latter only works if a real ReadLine interface module is installed).

       The most common uses of the interactive modes are

       Searching for authors, bundles, distribution files and modules
         There  are corresponding one-letter commands "a", "b", "d", and "m" for each of the four categories and
         another, "i" for any of the mentioned four. Each of the four entities is implemented as  a  class  with
         slightly differing methods for displaying an object.

         Arguments to these commands are either strings exactly matching the identification string of an object,
         or regular expressions matched case-insensitively against various attributes of the objects. The parser
         only recognizes a regular expression when you enclose it with slashes.

         The  principle  is  that the number of objects found influences how an item is displayed. If the search
         finds one item, the result is displayed with the rather verbose method "as_string", but  if  more  than
         one is found, each object is displayed with the terse method "as_glimpse".

         Examples:

           cpan> m Acme::MetaSyntactic
           Module id = Acme::MetaSyntactic
               CPAN_USERID  BOOK (Philippe Bruhat (BooK) <[...]>)
               CPAN_VERSION 0.99
               CPAN_FILE    B/BO/BOOK/Acme-MetaSyntactic-0.99.tar.gz
               UPLOAD_DATE  2006-11-06
               MANPAGE      Acme::MetaSyntactic - Themed metasyntactic variables names
               INST_FILE    /usr/local/lib/perl/5.10.0/Acme/MetaSyntactic.pm
               INST_VERSION 0.99
           cpan> a BOOK
           Author id = BOOK
               EMAIL        [...]
               FULLNAME     Philippe Bruhat (BooK)
           cpan> d BOOK/Acme-MetaSyntactic-0.99.tar.gz
           Distribution id = B/BO/BOOK/Acme-MetaSyntactic-0.99.tar.gz
               CPAN_USERID  BOOK (Philippe Bruhat (BooK) <[...]>)
               CONTAINSMODS Acme::MetaSyntactic Acme::MetaSyntactic::Alias [...]
               UPLOAD_DATE  2006-11-06
           cpan> m /lorem/
           Module  = Acme::MetaSyntactic::loremipsum (BOOK/Acme-MetaSyntactic-0.99.tar.gz)
           Module    Text::Lorem            (ADEOLA/Text-Lorem-0.3.tar.gz)
           Module    Text::Lorem::More      (RKRIMEN/Text-Lorem-More-0.12.tar.gz)
           Module    Text::Lorem::More::Source (RKRIMEN/Text-Lorem-More-0.12.tar.gz)
           cpan> i /berlin/
           Distribution    BEATNIK/Filter-NumberLines-0.02.tar.gz
           Module  = DateTime::TimeZone::Europe::Berlin (DROLSKY/DateTime-TimeZone-0.7904.tar.gz)
           Module    Filter::NumberLines    (BEATNIK/Filter-NumberLines-0.02.tar.gz)
           Author          [...]

         The  examples  illustrate  several aspects: the first three queries target modules, authors, or distros
         directly and yield exactly one result. The last two use regular expressions and yield several  results.
         The  last  one targets all of bundles, modules, authors, and distros simultaneously. When more than one
         result is available, they are printed in one-line format.

       "get", "make", "test", "install", "clean" modules or distributions
         These commands take any number of arguments and investigate what is necessary to  perform  the  action.
         Argument processing is as follows:

           known module name in format Foo/Bar.pm   module
           other embedded slash                     distribution
             - with trailing slash dot              directory
           enclosing slashes                        regexp
           known module name in format Foo::Bar     module

         If the argument is a distribution file name (recognized by embedded slashes), it is processed. If it is
         a  module,  CPAN  determines the distribution file in which this module is included and processes that,
         following any dependencies named in the module's META.yml or Makefile.PL (this behavior  is  controlled
         by  the  configuration  parameter  "prerequisites_policy"). If an argument is enclosed in slashes it is
         treated as a regular expression: it is expanded and if the result is  a  single  object  (distribution,
         bundle or module), this object is processed.

         Example:

             install Dummy::Perl                   # installs the module
             install AUXXX/Dummy-Perl-3.14.tar.gz  # installs that distribution
             install /Dummy-Perl-3.14/             # same if the regexp is unambiguous

         "get"  downloads  a  distribution  file and untars or unzips it, "make" builds it, "test" runs the test
         suite, and "install" installs it.

         Any "make" or "test" is run unconditionally. An

           install <distribution_file>

         is also run unconditionally. But for

           install <module>

         CPAN checks whether an install is needed and  prints  module  up  to  date  if  the  distribution  file
         containing the module doesn't need updating.

         CPAN also keeps track of what it has done within the current session and doesn't try to build a package
         a  second time regardless of whether it succeeded or not. It does not repeat a test run if the test has
         been run successfully before. Same for install runs.

         The "force" pragma may precede another command (currently: "get",  "make",  "test",  or  "install")  to
         execute  the command from scratch and attempt to continue past certain errors. See the section below on
         the "force" and the "fforce" pragma.

         The "notest" pragma skips the test part in the build process.

         Example:

             cpan> notest install Tk

         A "clean" command results in a

           make clean

         being executed within the distribution file's working directory.

       "readme", "perldoc", "look" module or distribution
         "readme" displays the README file of the associated distribution.  "Look" gets and untars (if  not  yet
         done)  the distribution file, changes to the appropriate directory and opens a subshell process in that
         directory. "perldoc" displays the module's pod documentation in html or plain text format.

       "ls" author
       "ls" globbing_expression
         The first form lists all distribution files in and below an author's CPAN directory as  stored  in  the
         CHECKSUMS files distributed on CPAN. The listing recurses into subdirectories.

         The second form limits or expands the output with shell globbing as in the following examples:

               ls JV/make*
               ls GSAR/*make*
               ls */*make*

         The  last  example  is  very slow and outputs extra progress indicators that break the alignment of the
         result.

         Note that globbing only lists directories explicitly  asked  for,  for  example  FOO/*  will  not  list
         FOO/bar/Acme-Sthg-n.nn.tar.gz.  This  may  be  regarded  as  a  bug  that may be changed in some future
         version.

       "failed"
         The "failed" command reports all distributions that failed on one of "make", "test"  or  "install"  for
         some reason in the currently running shell session.

       Persistence between sessions
         If  the "YAML" or the "YAML::Syck" module is installed a record of the internal state of all modules is
         written to disk after each step.  The files contain a signature of the currently running  perl  version
         for later perusal.

         If  the  configurations  variable  "build_dir_reuse"  is  set  to  a true value, then CPAN.pm reads the
         collected YAML files. If the stored signature matches the currently running perl, the stored  state  is
         loaded into memory such that persistence between sessions is effectively established.

       The "force" and the "fforce" pragma
         To  speed  things up in complex installation scenarios, CPAN.pm keeps track of what it has already done
         and refuses to do some things a second time. A "get", a "make", and an "install" are not  repeated.   A
         "test"  is  repeated  only  if  the previous test was unsuccessful. The diagnostic message when CPAN.pm
         refuses to do something a second time is one of Has already been  "unwrapped|made|tested  successfully"
         or  something similar. Another situation where CPAN refuses to act is an "install" if the corresponding
         "test" was not successful.

         In all these cases, the user can override this stubborn behaviour by prepending the  command  with  the
         word force, for example:

           cpan> force get Foo
           cpan> force make AUTHOR/Bar-3.14.tar.gz
           cpan> force test Baz
           cpan> force install Acme::Meta

         Each forced command is executed with the corresponding part of its memory erased.

         The "fforce" pragma is a variant that emulates a "force get" which erases the entire memory followed by
         the action specified, effectively restarting the whole get/make/test/install procedure from scratch.

       Lockfile
         Interactive  sessions  maintain  a  lockfile, by default "~/.cpan/.lock".  Batch jobs can run without a
         lockfile and not disturb each other.

         The shell offers to run in downgraded mode when another process is holding the  lockfile.  This  is  an
         experimental  feature  that  is  not  yet  tested  very well. This second shell then does not write the
         history file, does not use the metadata file, and has a different prompt.

       Signals
         CPAN.pm installs signal handlers for SIGINT and SIGTERM.  While  you  are  in  the  cpan-shell,  it  is
         intended  that you can press "^C" anytime and return to the cpan-shell prompt. A SIGTERM will cause the
         cpan-shell to clean up and leave the shell loop. You can emulate the effect of a SIGTERM by sending two
         consecutive SIGINTs, which usually means by pressing "^C" twice.

         CPAN.pm ignores SIGPIPE. If the user sets "inactivity_timeout", a SIGALRM is used during the run of the
         "perl Makefile.PL" or "perl Build.PL" subprocess. A SIGALRM is also used during module version parsing,
         and is controlled by "version_timeout".

   CPAN::Shell
       The commands available in the shell interface are methods in the package CPAN::Shell. If  you  enter  the
       shell  command,  your  input is split by the Text::ParseWords::shellwords() routine, which acts like most
       shells do. The first word is interpreted as the method to be invoked, and  the  rest  of  the  words  are
       treated  as  the  method's  arguments.   Continuation lines are supported by ending a line with a literal
       backslash.

   autobundle
       "autobundle" writes a bundle  file  into  the  "$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.
       Duplicates of each distribution are suppressed.  The name of the bundle file is based on the current date
       and  a  counter,  e.g.  Bundle/Snapshot_2012_05_21_00.pm.  This  is  installed  again  by  running  "cpan
       Bundle::Snapshot_2012_05_21_00", or installing "Bundle::Snapshot_2012_05_21_00" from the CPAN shell.

       Return value: path to the written file.

   hosts
       Note: this feature is still in alpha state and may change in future versions of CPAN.pm

       This  commands  provides  a  statistical  overview  over recent download activities. The data for this is
       collected in the YAML file "FTPstats.yml" in your "cpan_home" directory. If no YAML module is  configured
       or YAML not installed, no stats are provided.

       install_tested
           Install  all  distributions  that  have been tested successfully but have not yet been installed. See
           also "is_tested".

       is_tested
           List all build directories of distributions that have been tested successfully but have not yet  been
           installed. See also "install_tested".

   mkmyconfig
       mkmyconfig() writes your own CPAN::MyConfig file into your "~/.cpan/" directory so that you can save your
       own preferences instead of the system-wide ones.

   r [Module|/Regexp/]...
       scans  current  perl  installation for modules that have a newer version available on CPAN and provides a
       list of them. If called without argument, all potential upgrades are listed; if called with arguments the
       list is filtered to the modules and regexps given as arguments.

       The listing looks something like this:

         Package namespace         installed    latest  in CPAN file
         CPAN                        1.94_64    1.9600  ANDK/CPAN-1.9600.tar.gz
         CPAN::Reporter               1.1801    1.1902  DAGOLDEN/CPAN-Reporter-1.1902.tar.gz
         YAML                           0.70      0.73  INGY/YAML-0.73.tar.gz
         YAML::Syck                     1.14      1.17  AVAR/YAML-Syck-1.17.tar.gz
         YAML::Tiny                     1.44      1.50  ADAMK/YAML-Tiny-1.50.tar.gz
         CGI                            3.43      3.55  MARKSTOS/CGI.pm-3.55.tar.gz
         Module::Build::YAML            1.40      1.41  DAGOLDEN/Module-Build-0.3800.tar.gz
         TAP::Parser::Result::YAML      3.22      3.23  ANDYA/Test-Harness-3.23.tar.gz
         YAML::XS                       0.34      0.35  INGY/YAML-LibYAML-0.35.tar.gz

       It suppresses duplicates in the column "in CPAN file"  such  that  distributions  with  many  upgradeable
       modules are listed only once.

       Note that the list is not sorted.

   recent ***EXPERIMENTAL COMMAND***
       The  "recent"  command  downloads  a  list  of recent uploads to CPAN and displays them slowly. While the
       command is running, a $SIG{INT} exits the loop after displaying the current item.

       Note: This command requires XML::LibXML installed.

       Note: This whole command currently is just a hack and will probably change in future versions of CPAN.pm,
       but the general approach will likely remain.

       Note: See also smoke

   recompile
       recompile() is a special command that takes no argument and runs the make/test/install cycle  with  brute
       force  over all installed dynamically loadable extensions (a.k.a. XS modules) with 'force' in effect. The
       primary purpose of this command is to finish a network installation. Imagine you  have  a  common  source
       tree  for  two different architectures. You decide to do a completely independent fresh installation. You
       start on one architecture with the help of a Bundle file produced earlier. CPAN installs the whole Bundle
       for you, but when you try to repeat the job on the second architecture, CPAN responds with a "Foo  up  to
       date" message for all modules. So you invoke CPAN's recompile on the second architecture and you're done.

       Another  popular use for "recompile" is to act as a rescue in case your perl breaks binary compatibility.
       If one of the modules that CPAN uses is in turn depending on binary compatibility (so you cannot run CPAN
       commands), then you should try the CPAN::Nox module for recovery.

   report Bundle|Distribution|Module
       The "report" command temporarily turns on the "test_report" config variable, then runs the  "force  test"
       command  with  the given arguments. The "force" pragma reruns the tests and repeats every step that might
       have failed before.

   smoke ***EXPERIMENTAL COMMAND***
       *** WARNING: this command downloads and executes software  from  CPAN  to  your  computer  of  completely
       unknown  status.  You  should  never  do  this  with your normal account and better have a dedicated well
       separated and secured machine to do this. ***

       The "smoke" command takes the list of recent uploads to CPAN as provided  by  the  "recent"  command  and
       tests  them all. While the command is running $SIG{INT} is defined to mean that the current item shall be
       skipped.

       Note: This whole command currently is just a hack and will probably change in future versions of CPAN.pm,
       but the general approach will likely remain.

       Note: See also recent

   upgrade [Module|/Regexp/]...
       The "upgrade" command first runs an "r" command with the given arguments and  then  installs  the  newest
       versions of all modules that were listed by that.

   The four "CPAN::*" Classes: Author, Bundle, Module, Distribution
       Although  it  may  be considered internal, the class hierarchy does matter for both users and programmer.
       CPAN.pm deals with the four classes mentioned above, and those  classes  all  share  a  set  of  methods.
       Classical  single  polymorphism  is  in effect. A metaclass object registers all objects of all kinds and
       indexes them with a string. The strings  referencing  objects  have  a  separated  namespace  (well,  not
       completely separated):

                Namespace                         Class

          words containing a "/" (slash)      Distribution
           words starting with Bundle::          Bundle
                 everything else            Module or Author

       Modules  know  their  associated  Distribution  objects.  They  always  refer to the most recent official
       release. Developers may mark their releases as unstable development versions (by inserting an  underscore
       into  the  module version number which will also be reflected in the distribution name when you run 'make
       dist'), so the really hottest and newest distribution is  not  always  the  default.   If  a  module  Foo
       circulates  on  CPAN in both version 1.23 and 1.23_90, CPAN.pm offers a convenient way to install version
       1.23 by saying

           install Foo

       This would install the  complete  distribution  file  (say  BAR/Foo-1.23.tar.gz)  with  all  accompanying
       material.  But if you would like to install version 1.23_90, you need to know where the distribution file
       resides  on  CPAN  relative  to  the  authors/id/  directory.  If  the  author  is  BAR,  this  might  be
       BAR/Foo-1.23_90.tar.gz; so you would have to say

           install BAR/Foo-1.23_90.tar.gz

       The first example will be driven by an object of the class CPAN::Module, the second by an object of class
       CPAN::Distribution.

   Integrating local directories
       Note: this feature is still in alpha state and may change in future versions of CPAN.pm

       Distribution  objects  are  normally distributions from the CPAN, but there is a slightly degenerate case
       for Distribution objects, too, of projects held on the local disk. These distribution  objects  have  the
       same  name  as  the  local  directory and end with a dot. A dot by itself is also allowed for the current
       directory at the time CPAN.pm was used. All actions such as "make", "test",  and  "install"  are  applied
       directly to that directory. This gives the command "cpan ." an interesting touch: while the normal mantra
       of installing a CPAN module without CPAN.pm is one of

           perl Makefile.PL                 perl Build.PL
                  ( go and get prerequisites )
           make                             ./Build
           make test                        ./Build test
           make install                     ./Build install

       the  command  "cpan  ." does all of this at once. It figures out which of the two mantras is appropriate,
       fetches and installs all prerequisites,  takes  care  of  them  recursively,  and  finally  finishes  the
       installation of the module in the current directory, be it a CPAN module or not.

       The  typical  usage case is for private modules or working copies of projects from remote repositories on
       the local disk.

   Redirection
       The usual shell redirection symbols " | " and ">" are recognized by the cpan shell only  when  surrounded
       by  whitespace. So piping to pager or redirecting output into a file works somewhat as in a normal shell,
       with the stipulation that you must type extra spaces.

   Plugin support ***EXPERIMENTAL***
       Plugins are objects that implement any of currently eight methods:

         pre_get
         post_get
         pre_make
         post_make
         pre_test
         post_test
         pre_install
         post_install

       The "plugin_list" configuration parameter holds a list of strings of the form

         Modulename=arg0,arg1,arg2,arg3,...

       eg:

         CPAN::Plugin::Flurb=dir,/opt/pkgs/flurb/raw,verbose,1

       At run time, each listed plugin is instantiated as a singleton object by running the equivalent  of  this
       pseudo code:

         my $plugin = <string representation from config>;
         <generate Modulename and arguments from $plugin>;
         my $p = $instance{$plugin} ||= Modulename->new($arg0,$arg1,...);

       The  generated  singletons  are  kept  around  from  instantiation  until  the  end of the shell session.
       <plugin_list> can be reconfigured at any time at run time. While the cpan shell is running, it checks all
       activated plugins at each of the 8 reference points listed above and runs the respective method if it  is
       implemented  for that object. The method is called with the active CPAN::Distribution object passed in as
       an argument.

CONFIGURATION

       When the CPAN module is used for the first time, a configuration dialogue tries to determine a couple  of
       site  specific  options.  The result of the dialog is stored in a hash reference  $CPAN::Config in a file
       CPAN/Config.pm.

       Default values  defined  in  the  CPAN/Config.pm  file  can  be  overridden  in  a  user  specific  file:
       CPAN/MyConfig.pm.  Such a file is best placed in "$HOME/.cpan/CPAN/MyConfig.pm", because "$HOME/.cpan" is
       added to the search path of the CPAN module before the use()  or  require()  statements.  The  mkmyconfig
       command writes this file for you.

       The "o conf" command has various bells and whistles:

       completion support
           If you have a ReadLine module installed, you can hit TAB at any point of the commandline and "o conf"
           will offer you completion for the built-in subcommands and/or config variable names.

       displaying some help: o conf help
           Displays a short help

       displaying current values: o conf [KEY]
           Displays  the  current  value(s)  for this config variable. Without KEY, displays all subcommands and
           config variables.

           Example:

             o conf shell

           If KEY starts and ends with a slash, the string in between is treated as  a  regular  expression  and
           only keys matching this regexp are displayed

           Example:

             o conf /color/

       changing of scalar values: o conf KEY VALUE
           Sets  the config variable KEY to VALUE. The empty string can be specified as usual in shells, with ''
           or ""

           Example:

             o conf wget /usr/bin/wget

       changing of list values: o conf KEY SHIFT|UNSHIFT|PUSH|POP|SPLICE|LIST
           If a config variable name ends with "list", it is a list.  "o  conf  KEY  shift"  removes  the  first
           element  of  the  list,  "o  conf KEY pop" removes the last element of the list. "o conf KEYS unshift
           LIST" prepends a list of values to the list, "o conf KEYS push LIST" appends a list of valued to  the
           list.

           Likewise, "o conf KEY splice LIST" passes the LIST to the corresponding splice command.

           Finally, any other list of arguments is taken as a new list value for the KEY variable discarding the
           previous value.

           Examples:

             o conf urllist unshift http://cpan.dev.local/CPAN
             o conf urllist splice 3 1
             o conf urllist http://cpan1.local http://cpan2.local ftp://ftp.perl.org

       reverting to saved: o conf defaults
           Reverts all config variables to the state in the saved config file.

       saving the config: o conf commit
           Saves  all  config  variables to the current config file (CPAN/Config.pm or CPAN/MyConfig.pm that was
           loaded at start).

       The configuration dialog can be started any time later again by issuing the command " o conf  init  "  in
       the  CPAN shell. A subset of the configuration dialog can be run by issuing "o conf init WORD" where WORD
       is any valid config variable or a regular expression.

   Config Variables
       The following keys in the hash reference $CPAN::Config are currently defined:

         allow_installing_module_downgrades
                            allow or disallow installing module downgrades
         allow_installing_outdated_dists
                            allow or disallow installing modules that are
                            indexed in the cpan index pointing to a distro
                            with a higher distro-version number
         applypatch         path to external prg
         auto_commit        commit all changes to config variables to disk
         build_cache        size of cache for directories to build modules
         build_dir          locally accessible directory to build modules
         build_dir_reuse    boolean if distros in build_dir are persistent
         build_requires_install_policy
                            to install or not to install when a module is
                            only needed for building. yes|no|ask/yes|ask/no
         bzip2              path to external prg
         cache_metadata     use serializer to cache metadata
         check_sigs         if signatures should be verified
         cleanup_after_install
                            remove build directory immediately after a
                            successful install and remember that for the
                            duration of the session
         colorize_debug     Term::ANSIColor attributes for debugging output
         colorize_output    boolean if Term::ANSIColor should colorize output
         colorize_print     Term::ANSIColor attributes for normal output
         colorize_warn      Term::ANSIColor attributes for warnings
         commandnumber_in_prompt
                            boolean if you want to see current command number
         commands_quote     preferred character to use for quoting external
                            commands when running them. Defaults to double
                            quote on Windows, single tick everywhere else;
                            can be set to space to disable quoting
         connect_to_internet_ok
                            whether to ask if opening a connection is ok before
                            urllist is specified
         cpan_home          local directory reserved for this package
         curl               path to external prg
         dontload_hash      DEPRECATED
         dontload_list      arrayref: modules in the list will not be
                            loaded by the CPAN::has_inst() routine
         ftp                path to external prg
         ftp_passive        if set, the environment variable FTP_PASSIVE is set
                            for downloads
         ftp_proxy          proxy host for ftp requests
         ftpstats_period    max number of days to keep download statistics
         ftpstats_size      max number of items to keep in the download statistics
         getcwd             see below
         gpg                path to external prg
         gzip               location of external program gzip
         halt_on_failure    stop processing after the first failure of queued
                            items or dependencies
         histfile           file to maintain history between sessions
         histsize           maximum number of lines to keep in histfile
         http_proxy         proxy host for http requests
         inactivity_timeout breaks interactive Makefile.PLs or Build.PLs
                            after this many seconds inactivity. Set to 0 to
                            disable timeouts.
         index_expire       refetch index files after this many days
         inhibit_startup_message
                            if true, suppress the startup message
         keep_source_where  directory in which to keep the source (if we do)
         load_module_verbosity
                            report loading of optional modules used by CPAN.pm
         lynx               path to external prg
         make               location of external make program
         make_arg           arguments that should always be passed to 'make'
         make_install_make_command
                            the make command for running 'make install', for
                            example 'sudo make'
         make_install_arg   same as make_arg for 'make install'
         makepl_arg         arguments passed to 'perl Makefile.PL'
         mbuild_arg         arguments passed to './Build'
         mbuild_install_arg arguments passed to './Build install'
         mbuild_install_build_command
                            command to use instead of './Build' when we are
                            in the install stage, for example 'sudo ./Build'
         mbuildpl_arg       arguments passed to 'perl Build.PL'
         ncftp              path to external prg
         ncftpget           path to external prg
         no_proxy           don't proxy to these hosts/domains (comma separated list)
         pager              location of external program more (or any pager)
         password           your password if you CPAN server wants one
         patch              path to external prg
         patches_dir        local directory containing patch files
         perl5lib_verbosity verbosity level for PERL5LIB additions
         plugin_list        list of active hooks (see Plugin support above
                            and the CPAN::Plugin module)
         prefer_external_tar
                            per default all untar operations are done with
                            Archive::Tar; by setting this variable to true
                            the external tar command is used if available
         prefer_installer   legal values are MB and EUMM: if a module comes
                            with both a Makefile.PL and a Build.PL, use the
                            former (EUMM) or the latter (MB); if the module
                            comes with only one of the two, that one will be
                            used no matter the setting
         prerequisites_policy
                            what to do if you are missing module prerequisites
                            ('follow' automatically, 'ask' me, or 'ignore')
                            For 'follow', also sets PERL_AUTOINSTALL and
                            PERL_EXTUTILS_AUTOINSTALL for "--defaultdeps" if
                            not already set
         prefs_dir          local directory to store per-distro build options
         proxy_user         username for accessing an authenticating proxy
         proxy_pass         password for accessing an authenticating proxy
         randomize_urllist  add some randomness to the sequence of the urllist
         recommends_policy  whether recommended prerequisites should be included
         scan_cache         controls scanning of cache ('atstart', 'atexit' or 'never')
         shell              your favorite shell
         show_unparsable_versions
                            boolean if r command tells which modules are versionless
         show_upload_date   boolean if commands should try to determine upload date
         show_zero_versions boolean if r command tells for which modules $version==0
         suggests_policy    whether suggested prerequisites should be included
         tar                location of external program tar
         tar_verbosity      verbosity level for the tar command
         term_is_latin      deprecated: if true Unicode is translated to ISO-8859-1
                            (and nonsense for characters outside latin range)
         term_ornaments     boolean to turn ReadLine ornamenting on/off
         test_report        email test reports (if CPAN::Reporter is installed)
         trust_test_report_history
                            skip testing when previously tested ok (according to
                            CPAN::Reporter history)
         unzip              location of external program unzip
         urllist            arrayref to nearby CPAN sites (or equivalent locations)
         urllist_ping_external
                            use external ping command when autoselecting mirrors
         urllist_ping_verbose
                            increase verbosity when autoselecting mirrors
         use_prompt_default set PERL_MM_USE_DEFAULT for configure/make/test/install
         use_sqlite         use CPAN::SQLite for metadata storage (fast and lean)
         username           your username if you CPAN server wants one
         version_timeout    stops version parsing after this many seconds.
                            Default is 15 secs. Set to 0 to disable.
         wait_list          arrayref to a wait server to try (See CPAN::WAIT)
         wget               path to external prg
         yaml_load_code     enable YAML code deserialisation via CPAN::DeferredCode
         yaml_module        which module to use to read/write YAML files

       You can set and query each of these options interactively in the cpan shell with the "o conf" or  the  "o
       conf init" command as specified below.

       "o conf <scalar option>"
         prints the current value of the scalar option

       "o conf <scalar option> <value>"
         Sets the value of the scalar option to value

       "o conf <list option>"
         prints the current value of the list option in MakeMaker's neatvalue format.

       "o conf <list option> [shift|pop]"
         shifts or pops the array in the list option variable

       "o conf <list option> [unshift|push|splice] <list>"
         works like the corresponding perl commands.

       interactive editing: o conf init [MATCH|LIST]
         Runs an interactive configuration dialog for matching variables.  Without argument runs the dialog over
         all supported config variables.  To specify a MATCH the argument must be enclosed by slashes.

         Examples:

           o conf init ftp_passive ftp_proxy
           o conf init /color/

         Note:  this method of setting config variables often provides more explanation about the functioning of
         a variable than the manpage.

   CPAN::anycwd($path): Note on config variable getcwd
       CPAN.pm changes the current working directory often and  needs  to  determine  its  own  current  working
       directory.  By  default  it  uses  Cwd::cwd,  but  if  for  some reason this doesn't work on your system,
       configure alternatives according to the following table:

       cwd Calls Cwd::cwd

       getcwd
           Calls Cwd::getcwd

       fastcwd
           Calls Cwd::fastcwd

       getdcwd
           Calls Cwd::getdcwd

       backtickcwd
           Calls the external command cwd.

   Note on the format of the urllist parameter
       urllist parameters are URLs according to RFC 1738. We do a little guessing if your URL is not  compliant,
       but if you have problems with "file" URLs, please try the correct format. Either:

           file://localhost/whatever/ftp/pub/CPAN/

       or

           file:///home/ftp/pub/CPAN/

   The urllist parameter has CD-ROM support
       The  "urllist"  parameter of the configuration table contains a list of URLs used for downloading. If the
       list contains any "file" URLs, CPAN always tries there first. This feature is disabled for  index  files.
       So  the  recommendation  for  the  owner  of a CD-ROM with CPAN contents is: include your local, possibly
       outdated CD-ROM as a "file" URL at the end of urllist, e.g.

         o conf urllist push file://localhost/CDROM/CPAN

       CPAN.pm will then fetch the index files from one of the CPAN sites that come at the beginning of urllist.
       It will later check for each module to see whether there is a local copy of the most recent version.

       Another peculiarity of urllist is that the site that we could  successfully  fetch  the  last  file  from
       automatically  gets a preference token and is tried as the first site for the next request. So if you add
       a new site at runtime it may happen that the previously preferred site will be tried another  time.  This
       means  that  if  you  want  to  disallow a site for the next transfer, it must be explicitly removed from
       urllist.

   Maintaining the urllist parameter
       If you have YAML.pm (or some other YAML module configured in "yaml_module") installed, CPAN.pm collects a
       few statistical data about recent downloads. You can view the statistics  with  the  "hosts"  command  or
       inspect them directly by looking into the "FTPstats.yml" file in your "cpan_home" directory.

       To  get  some  interesting statistics, it is recommended that "randomize_urllist" be set; this introduces
       some amount of randomness into the URL selection.

   The "requires" and "build_requires" dependency declarations
       Since CPAN.pm version 1.88_51  modules  declared  as  "build_requires"  by  a  distribution  are  treated
       differently    depending   on   the   config   variable   "build_requires_install_policy".   By   setting
       "build_requires_install_policy" to "no", such a module is not installed. It is only built and tested, and
       then kept in the list of tested but uninstalled modules. As such, it is available during the build of the
       dependent module by integrating the path to the "blib/arch" and "blib/lib" directories in the environment
       variable PERL5LIB. If "build_requires_install_policy" is set to "yes",  then  both  modules  declared  as
       "requires" and those declared as "build_requires" are treated alike. By setting to "ask/yes" or "ask/no",
       CPAN.pm asks the user and sets the default accordingly.

   Configuration of the allow_installing_* parameters
       The  "allow_installing_*"  parameters  are evaluated during the "make" phase. If set to "yes", they allow
       the testing and the installation of the current distro and otherwise have no effect. If set to "no", they
       may abort the build (preventing testing and  installing),  depending  on  the  contents  of  the  "blib/"
       directory.  The  "blib/"  directory  is  the  directory  that  holds  all the files that would usually be
       installed in the "install" phase.

       "allow_installing_outdated_dists" compares the "blib/" directory  with  the  CPAN  index.   If  it  finds
       something there that belongs, according to the index, to a different dist, it aborts the current build.

       "allow_installing_module_downgrades"  compares  the  "blib/"  directory  with  already installed modules,
       actually their version numbers, as determined by ExtUtils::MakeMaker or equivalent. If a  to-be-installed
       module would downgrade an already installed module, the current build is aborted.

       An  interesting twist occurs when a distroprefs document demands the installation of an outdated dist via
       goto while "allow_installing_outdated_dists" forbids it. Without additional provisions,  this  would  let
       the  "allow_installing_outdated_dists"  win and the distroprefs lose. So the proper arrangement in such a
       case is to write a second distroprefs document for the distro that "goto"  points  to  and  overrule  the
       "cpanconfig" there. E.g.:

         ---
         match:
           distribution: "^MAUKE/Keyword-Simple-0.04.tar.gz"
         goto: "MAUKE/Keyword-Simple-0.03.tar.gz"
         ---
         match:
           distribution: "^MAUKE/Keyword-Simple-0.03.tar.gz"
         cpanconfig:
           allow_installing_outdated_dists: yes

   Configuration for individual distributions (Distroprefs)
       (Note: This feature has been introduced in CPAN.pm 1.8854)

       Distributions  on  CPAN  usually behave according to what we call the CPAN mantra. Or since the advent of
       Module::Build we should talk about two mantras:

           perl Makefile.PL     perl Build.PL
           make                 ./Build
           make test            ./Build test
           make install         ./Build install

       But some modules cannot be built with this mantra. They try to get some extra data from the user via  the
       environment,  extra  arguments,  or interactively--thus disturbing the installation of large bundles like
       Phalanx100 or modules with many dependencies like Plagger.

       The distroprefs system of "CPAN.pm" addresses  this  problem  by  allowing  the  user  to  specify  extra
       informations and recipes in YAML files to either

       •   pass additional arguments to one of the four commands,

       •   set environment variables

       •   instantiate  an  Expect  object  that  reads from the console, waits for some regular expressions and
           enters some answers

       •   temporarily override assorted "CPAN.pm" configuration variables

       •   specify dependencies the original maintainer forgot

       •   disable the installation of an object altogether

       See the YAML and Data::Dumper files that come with  the  "CPAN.pm"  distribution  in  the  "distroprefs/"
       directory for examples.

   Filenames
       The YAML files themselves must have the ".yml" extension; all other files are ignored (for two exceptions
       see  Fallback Data::Dumper and Storable below). The containing directory can be specified in "CPAN.pm" in
       the "prefs_dir" config variable. Try "o conf init prefs_dir" in the CPAN shell to set  and  activate  the
       distroprefs system.

       Every  YAML  file may contain arbitrary documents according to the YAML specification, and every document
       is treated as an entity that can specify the treatment of a single distribution.

       Filenames can be picked arbitrarily; "CPAN.pm" always reads all files (in alphabetical order)  and  takes
       the  key  "match"  (see below in Language Specs) as a hashref containing match criteria that determine if
       the current distribution matches the YAML document or not.

   Fallback Data::Dumper and Storable
       If neither your  configured  "yaml_module"  nor  YAML.pm  is  installed,  CPAN.pm  falls  back  to  using
       Data::Dumper  and  Storable  and  looks  for  files with the extensions ".dd" or ".st" in the "prefs_dir"
       directory. These files are expected to contain one or more hashrefs.  For Data::Dumper  generated  files,
       this  is  expected to be done with by defining $VAR1, $VAR2, etc. The YAML shell would produce these with
       the command

           ysh < somefile.yml > somefile.dd

       For Storable files the rule is that they must be constructed such that "Storable::retrieve(file)" returns
       an array reference and the array elements represent one distropref object each. The conversion from  YAML
       would look like so:

           perl -MYAML=LoadFile -MStorable=nstore -e '
               @y=LoadFile(shift);
               nstore(\@y, shift)' somefile.yml somefile.st

       In  bootstrapping  situations it is usually sufficient to translate only a few YAML files to Data::Dumper
       for  crucial  modules  like  "YAML::Syck",  "YAML.pm"  and  "Expect.pm".  If  you  prefer  Storable  over
       Data::Dumper,  remember  to  pull  out  a Storable version that writes an older format than all the other
       Storable versions that will need to read them.

   Blueprint
       The following example contains all supported keywords and structures  with  the  exception  of  "eexpect"
       which can be used instead of "expect".

         ---
         comment: "Demo"
         match:
           module: "Dancing::Queen"
           distribution: "^CHACHACHA/Dancing-"
           not_distribution: "\.zip$"
           perl: "/usr/local/cariba-perl/bin/perl"
           perlconfig:
             archname: "freebsd"
             not_cc: "gcc"
           env:
             DANCING_FLOOR: "Shubiduh"
         disabled: 1
         cpanconfig:
           make: gmake
         pl:
           args:
             - "--somearg=specialcase"

           env: {}

           expect:
             - "Which is your favorite fruit"
             - "apple\n"

         make:
           args:
             - all
             - extra-all

           env: {}

           expect: []

           commandline: "echo SKIPPING make"

         test:
           args: []

           env: {}

           expect: []

         install:
           args: []

           env:
             WANT_TO_INSTALL: YES

           expect:
             - "Do you really want to install"
             - "y\n"

         patches:
           - "ABCDE/Fedcba-3.14-ABCDE-01.patch"

         depends:
           configure_requires:
             LWP: 5.8
           build_requires:
             Test::Exception: 0.25
           requires:
             Spiffy: 0.30

   Language Specs
       Every YAML document represents a single hash reference. The valid keys in this hash are as follows:

       comment [scalar]
           A comment

       cpanconfig [hash]
           Temporarily override assorted "CPAN.pm" configuration variables.

           Supported  are:  "build_requires_install_policy",  "check_sigs", "make", "make_install_make_command",
           "prefer_installer", "test_report". Please report as a bug when you need another one supported.

       depends [hash] *** EXPERIMENTAL FEATURE ***
           All three types, namely "configure_requires", "build_requires", and "requires" are supported  in  the
           way  specified  in  the  META.yml  specification.  The  current  implementation  merges the specified
           dependencies with those declared by the package maintainer. In a future implementation  this  may  be
           changed to override the original declaration.

       disabled [boolean]
           Specifies that this distribution shall not be processed at all.

       features [array] *** EXPERIMENTAL FEATURE ***
           Experimental  implementation  to  deal with optional_features from META.yml. Still needs coordination
           with installer software and currently works only for META.yml declaring "dynamic_config=0". Use  with
           caution.

       goto [string]
           The canonical name of a delegate distribution to install instead. Useful when a new version, although
           it  tests  OK itself, breaks something else or a developer release or a fork is already uploaded that
           is better than the last released version.

       install [hash]
           Processing instructions for the "make install" or "./Build install" phase of  the  CPAN  mantra.  See
           below under Processing Instructions.

       make [hash]
           Processing  instructions  for  the  "make"  or  "./Build"  phase  of the CPAN mantra. See below under
           Processing Instructions.

       match [hash]
           A hashref with one or more of the keys "distribution", "module", "perl", "perlconfig", and "env" that
           specify whether a document is targeted  at  a  specific  CPAN  distribution  or  installation.   Keys
           prefixed with "not_" negates the corresponding match.

           The  corresponding values are interpreted as regular expressions. The "distribution" related one will
           be matched against the canonical distribution name, e.g. "AUTHOR/Foo-Bar-3.14.tar.gz".

           The "module" related one will be matched against all modules contained in the distribution until  one
           module matches.

           The "perl" related one will be matched against $^X (but with the absolute path).

           The  value  associated  with  "perlconfig"  is itself a hashref that is matched against corresponding
           values in the %Config::Config hash living in the  "Config.pm"  module.   Keys  prefixed  with  "not_"
           negates the corresponding match.

           The  value  associated with "env" is itself a hashref that is matched against corresponding values in
           the %ENV hash.  Keys prefixed with "not_" negates the corresponding match.

           If more than one restriction of "module", "distribution", etc.  is  specified,  the  results  of  the
           separately  computed match values must all match. If so, the hashref represented by the YAML document
           is returned as the preference structure for the current distribution.

       patches [array]
           An array of patches on CPAN or on the local disk to  be  applied  in  order  via  an  external  patch
           program. If the value for the "-p" parameter is 0 or 1 is determined by reading the patch beforehand.
           The  path  to  each  patch  is either an absolute path on the local filesystem or relative to a patch
           directory specified in the "patches_dir" configuration variable or  in  the  format  of  a  canonical
           distro  name.  For  examples  please  consult  the distroprefs/ directory in the CPAN.pm distribution
           (these examples are not installed by default).

           Note: if the "applypatch" program is installed and "CPAN::Config" knows  about  it  and  a  patch  is
           written  by  the  "makepatch"  program,  then  "CPAN.pm"  lets  "applypatch"  apply  the  patch. Both
           "makepatch" and "applypatch" are available from CPAN in the "JV/makepatch-*" distribution.

       pl [hash]
           Processing instructions for the "perl Makefile.PL" or "perl Build.PL" phase of the CPAN  mantra.  See
           below under Processing Instructions.

       test [hash]
           Processing  instructions  for  the  "make test" or "./Build test" phase of the CPAN mantra. See below
           under Processing Instructions.

   Processing Instructions
       args [array]
           Arguments to be added to the command line

       commandline
           A full commandline to run via "system()".  During execution, the environment variable PERL is set  to
           $^X (but with an absolute path). If "commandline" is specified, "args" is not used.

       eexpect [hash]
           Extended  "expect".  This is a hash reference with four allowed keys, "mode", "timeout", "reuse", and
           "talk".

           You must install the "Expect" module to use "eexpect". CPAN.pm does not install it for you.

           "mode" may have the values "deterministic" for the case where all questions come in the order written
           down and "anyorder" for the case where the questions may come in  any  order.  The  default  mode  is
           "deterministic".

           "timeout"  denotes  a  timeout in seconds. Floating-point timeouts are OK. With "mode=deterministic",
           the timeout denotes the timeout per question; with "mode=anyorder" it denotes the  timeout  per  byte
           received from the stream or questions.

           "talk"  is  a  reference  to  an array that contains alternating questions and answers. Questions are
           regular expressions and answers are literal strings. The Expect module watches the  stream  from  the
           execution of the external program ("perl Makefile.PL", "perl Build.PL", "make", etc.).

           For  "mode=deterministic", the CPAN.pm injects the corresponding answer as soon as the stream matches
           the regular expression.

           For "mode=anyorder" CPAN.pm answers a question as soon as the timeout is reached for the next byte in
           the input stream. In this mode you can use the "reuse" parameter to decide what will  happen  with  a
           question-answer  pair  after  it  has been used. In the default case (reuse=0) it is removed from the
           array, avoiding being used again accidentally. If you want to answer the question "Do you really want
           to do that" several times, then it must be included in the array at least as often as you  want  this
           answer to be given. Setting the parameter "reuse" to 1 makes this repetition unnecessary.

       env [hash]
           Environment variables to be set during the command

       expect [array]
           You must install the "Expect" module to use "expect". CPAN.pm does not install it for you.

           "expect: <array>" is a short notation for this "eexpect":

                   eexpect:
                           mode: deterministic
                           timeout: 15
                           talk: <array>

   Schema verification with "Kwalify"
       If  you  have  the  "Kwalify"  module  installed  (which  is  part of the Bundle::CPANxxl), then all your
       distroprefs files are checked for syntactic correctness.

   Example Distroprefs Files
       "CPAN.pm" comes with a collection of example YAML files. Note that these are  really  just  examples  and
       should  not  be  used without care because they cannot fit everybody's purpose. After all, the authors of
       the packages that ask questions had a need to ask, so you should watch their  questions  and  adjust  the
       examples to your environment and your needs. You have been warned:-)

PROGRAMMER'S INTERFACE

       If you do not enter the shell, shell commands are available both as methods ("CPAN::Shell->install(...)")
       and  as  functions  in the calling package ("install(...)").  Before calling low-level commands, it makes
       sense to initialize components of CPAN you need, e.g.:

         CPAN::HandleConfig->load;
         CPAN::Shell::setup_output;
         CPAN::Index->reload;

       High-level commands do such initializations automatically.

       There's currently only one class that has a  stable  interface  -  CPAN::Shell.  All  commands  that  are
       available  in  the  CPAN shell are methods of the class CPAN::Shell. The arguments on the commandline are
       passed as arguments to the method.

       So if you take for example the shell command

         notest install A B C

       the actually executed command is

         CPAN::Shell->notest("install","A","B","C");

       Each of the commands that produce listings of modules ("r", "autobundle", "u") also return a list of  the
       IDs of all modules within the list.

       expand($type,@things)
         The IDs of all objects available within a program are strings that can be expanded to the corresponding
         real  objects  with  the  "CPAN::Shell->expand("Module",@things)"  method.  Expand  returns  a  list of
         CPAN::Module objects according to the @things arguments given. In scalar context, it returns  only  the
         first element of the list.

       expandany(@things)
         Like  expand,  but  returns  objects  of  the appropriate type, i.e.  CPAN::Bundle objects for bundles,
         CPAN::Module objects for modules, and CPAN::Distribution objects for distributions. Note: it  does  not
         expand to CPAN::Author objects.

       Programming Examples
         This  enables  the  programmer  to do operations that combine functionalities that are available in the
         shell.

             # install everything that is outdated on my disk:
             perl -MCPAN -e 'CPAN::Shell->install(CPAN::Shell->r)'

             # install my favorite programs if necessary:
             for $mod (qw(Net::FTP Digest::SHA Data::Dumper)) {
                 CPAN::Shell->install($mod);
             }

             # list all modules on my disk that have no VERSION number
             for $mod (CPAN::Shell->expand("Module","/./")) {
                 next unless $mod->inst_file;
                 # MakeMaker convention for undefined $VERSION:
                 next unless $mod->inst_version eq "undef";
                 print "No VERSION in ", $mod->id, "\n";
             }

             # find out which distribution on CPAN contains a module:
             print CPAN::Shell->expand("Module","Apache::Constants")->cpan_file

         Or if you want to schedule a cron job to watch CPAN, you could list all  modules  that  need  updating.
         First a quick and dirty way:

             perl -e 'use CPAN; CPAN::Shell->r;'

         If  you  don't  want any output should all modules be up to date, parse the output of above command for
         the regular expression "/modules are up to date/" and decide to mail the  output  only  if  it  doesn't
         match.

         If  you  prefer  to  do it more in a programmerish style in one single process, something like this may
         better suit you:

           # list all modules on my disk that have newer versions on CPAN
           for $mod (CPAN::Shell->expand("Module","/./")) {
             next unless $mod->inst_file;
             next if $mod->uptodate;
             printf "Module %s is installed as %s, could be updated to %s from CPAN\n",
                 $mod->id, $mod->inst_version, $mod->cpan_version;
           }

         If that gives too much output every day, you may want to watch only for three modules. You can write

           for $mod (CPAN::Shell->expand("Module","/Apache|LWP|CGI/")) {

         as the first line instead. Or you can combine some of the above tricks:

           # watch only for a new mod_perl module
           $mod = CPAN::Shell->expand("Module","mod_perl");
           exit if $mod->uptodate;
           # new mod_perl arrived, let me know all update recommendations
           CPAN::Shell->r;

   Methods in the other Classes
       CPAN::Author::as_glimpse()
           Returns a one-line description of the author

       CPAN::Author::as_string()
           Returns a multi-line description of the author

       CPAN::Author::email()
           Returns the author's email address

       CPAN::Author::fullname()
           Returns the author's name

       CPAN::Author::name()
           An alias for fullname

       CPAN::Bundle::as_glimpse()
           Returns a one-line description of the bundle

       CPAN::Bundle::as_string()
           Returns a multi-line description of the bundle

       CPAN::Bundle::clean()
           Recursively runs the "clean" method on all items contained in the bundle.

       CPAN::Bundle::contains()
           Returns a list of objects' IDs contained in a bundle. The associated objects may be bundles,  modules
           or distributions.

       CPAN::Bundle::force($method,@args)
           Forces  CPAN  to perform a task that it normally would have refused to do. Force takes as arguments a
           method name to be called and any number of additional arguments that should be passed to  the  called
           method.   The  internals of the object get the needed changes so that CPAN.pm does not refuse to take
           the action. The "force" is passed recursively to all contained objects. See also the section above on
           the "force" and the "fforce" pragma.

       CPAN::Bundle::get()
           Recursively runs the "get" method on all items contained in the bundle

       CPAN::Bundle::inst_file()
           Returns the highest installed version of the bundle in either @INC  or  "$CPAN::Config->{cpan_home}".
           Note that this is different from CPAN::Module::inst_file.

       CPAN::Bundle::inst_version()
           Like CPAN::Bundle::inst_file, but returns the $VERSION

       CPAN::Bundle::uptodate()
           Returns 1 if the bundle itself and all its members are up-to-date.

       CPAN::Bundle::install()
           Recursively runs the "install" method on all items contained in the bundle

       CPAN::Bundle::make()
           Recursively runs the "make" method on all items contained in the bundle

       CPAN::Bundle::readme()
           Recursively runs the "readme" method on all items contained in the bundle

       CPAN::Bundle::test()
           Recursively runs the "test" method on all items contained in the bundle

       CPAN::Distribution::as_glimpse()
           Returns a one-line description of the distribution

       CPAN::Distribution::as_string()
           Returns a multi-line description of the distribution

       CPAN::Distribution::author
           Returns the CPAN::Author object of the maintainer who uploaded this distribution

       CPAN::Distribution::pretty_id()
           Returns  a string of the form "AUTHORID/TARBALL", where AUTHORID is the author's PAUSE ID and TARBALL
           is the distribution filename.

       CPAN::Distribution::base_id()
           Returns the distribution filename without any archive suffix.  E.g "Foo-Bar-0.01"

       CPAN::Distribution::clean()
           Changes to the directory where the distribution has been unpacked and runs "make clean" there.

       CPAN::Distribution::containsmods()
           Returns a list of IDs of modules contained in a distribution  file.   Works  only  for  distributions
           listed in the 02packages.details.txt.gz file. This typically means that just most recent version of a
           distribution is covered.

       CPAN::Distribution::cvs_import()
           Changes to the directory where the distribution has been unpacked and runs something like

               cvs -d $cvs_root import -m $cvs_log $cvs_dir $userid v$version

           there.

       CPAN::Distribution::dir()
           Returns the directory into which this distribution has been unpacked.

       CPAN::Distribution::force($method,@args)
           Forces  CPAN  to perform a task that it normally would have refused to do. Force takes as arguments a
           method name to be called and any number of additional arguments that should be passed to  the  called
           method.   The  internals of the object get the needed changes so that CPAN.pm does not refuse to take
           the action. See also the section above on the "force" and the "fforce" pragma.

       CPAN::Distribution::get()
           Downloads the distribution from CPAN and unpacks it. Does nothing if  the  distribution  has  already
           been downloaded and unpacked within the current session.

       CPAN::Distribution::install()
           Changes to the directory where the distribution has been unpacked and runs the external command "make
           install"  there. If "make" has not yet been run, it will be run first. A "make test" is issued in any
           case and if this fails, the install is cancelled. The cancellation can be avoided by letting  "force"
           run the "install" for you.

           This  install  method  only has the power to install the distribution if there are no dependencies in
           the way. To install an object along with all its dependencies, use CPAN::Shell->install.

           Note that install() gives no meaningful return value. See uptodate().

       CPAN::Distribution::isa_perl()
           Returns 1 if this distribution file seems to be a perl distribution.  Normally this is  derived  from
           the  file name only, but the index from CPAN can contain a hint to achieve a return value of true for
           other filenames too.

       CPAN::Distribution::look()
           Changes to the directory where the distribution has been unpacked and opens a subshell there. Exiting
           the subshell returns.

       CPAN::Distribution::make()
           First runs the "get" method to make sure the distribution is downloaded and unpacked. Changes to  the
           directory  where the distribution has been unpacked and runs the external commands "perl Makefile.PL"
           or "perl Build.PL" and "make" there.

       CPAN::Distribution::perldoc()
           Downloads the pod documentation of the file associated with a distribution (in HTML format) and  runs
           it  through  the external command lynx specified in "$CPAN::Config->{lynx}". If lynx isn't available,
           it converts it to plain text with the external command  html2text  and  runs  it  through  the  pager
           specified in "$CPAN::Config->{pager}".

       CPAN::Distribution::prefs()
           Returns  the  hash  reference  from  the  first matching YAML file that the user has deposited in the
           "prefs_dir/" directory. The first succeeding match wins. The files in the "prefs_dir/" are  processed
           alphabetically,  and  the canonical distro name (e.g.  AUTHOR/Foo-Bar-3.14.tar.gz) is matched against
           the regular expressions stored in the $root->{match}{distribution} attribute value.  Additionally all
           module names contained in  a  distribution  are  matched  against  the  regular  expressions  in  the
           $root->{match}{module}  attribute  value.  The  two  match values are ANDed together. Each of the two
           attributes are optional.

       CPAN::Distribution::prereq_pm()
           Returns the hash reference  that  has  been  announced  by  a  distribution  as  the  "requires"  and
           "build_requires"  elements.  These can be declared either by the "META.yml" (if authoritative) or can
           be deposited after the run of  "Build.PL"  in  the  file  "./_build/prereqs"  or  after  the  run  of
           "Makfile.PL"  written  as  the  "PREREQ_PM"  hash in a comment in the produced "Makefile". Note: this
           method only works after an attempt has been made to "make" the distribution. Returns undef otherwise.

       CPAN::Distribution::readme()
           Downloads the README file associated with a distribution and runs it through the pager  specified  in
           "$CPAN::Config->{pager}".

       CPAN::Distribution::reports()
           Downloads report data for this distribution from www.cpantesters.org and displays a subset of them.

       CPAN::Distribution::read_yaml()
           Returns  the  content  of the META.yml of this distro as a hashref. Note: works only after an attempt
           has been made to "make" the distribution.  Returns undef otherwise. Also returns undef if the content
           of META.yml is not authoritative. (The rules about what exactly makes the content  authoritative  are
           still in flux.)

       CPAN::Distribution::test()
           Changes to the directory where the distribution has been unpacked and runs "make test" there.

       CPAN::Distribution::uptodate()
           Returns 1 if all the modules contained in the distribution are up-to-date. Relies on containsmods.

       CPAN::Index::force_reload()
           Forces a reload of all indices.

       CPAN::Index::reload()
           Reloads all indices if they have not been read for more than "$CPAN::Config->{index_expire}" days.

       CPAN::InfoObj::dump()
           CPAN::Author,  CPAN::Bundle,  CPAN::Module, and CPAN::Distribution inherit this method. It prints the
           data structure associated with  an  object.  Useful  for  debugging.  Note:  the  data  structure  is
           considered internal and thus subject to change without notice.

       CPAN::Module::as_glimpse()
           Returns  a  one-line  description  of  the module in four columns: The first column contains the word
           "Module", the second column consists of one character: an equals  sign  if  this  module  is  already
           installed  and  up-to-date,  a  less-than sign if this module is installed but can be upgraded, and a
           space if the module is not installed. The third column is the name  of  the  module  and  the  fourth
           column gives maintainer or distribution information.

       CPAN::Module::as_string()
           Returns a multi-line description of the module

       CPAN::Module::clean()
           Runs a clean on the distribution associated with this module.

       CPAN::Module::cpan_file()
           Returns the filename on CPAN that is associated with the module.

       CPAN::Module::cpan_version()
           Returns the latest version of this module available on CPAN.

       CPAN::Module::cvs_import()
           Runs a cvs_import on the distribution associated with this module.

       CPAN::Module::description()
           Returns  a  44  character description of this module. Only available for modules listed in The Module
           List (CPAN/modules/00modlist.long.html or 00modlist.long.txt.gz)

       CPAN::Module::distribution()
           Returns the CPAN::Distribution object that contains the current version of this module.

       CPAN::Module::dslip_status()
           Returns a hash reference. The keys of the hash are the letters "D",  "S",  "L",  "I",  and  <P>,  for
           development  status, support level, language, interface and public licence respectively. The data for
           the DSLIP status are collected by pause.perl.org when authors register their namespaces.  The  values
           of  the  5 hash elements are one-character words whose meaning is described in the table below. There
           are also 5 hash elements "DV", "SV", "LV", "IV", and <PV> that carry a more verbose value  of  the  5
           status variables.

           Where the 'DSLIP' characters have the following meanings:

             D - Development Stage  (Note: *NO IMPLIED TIMESCALES*):
               i   - Idea, listed to gain consensus or as a placeholder
               c   - under construction but pre-alpha (not yet released)
               a/b - Alpha/Beta testing
               R   - Released
               M   - Mature (no rigorous definition)
               S   - Standard, supplied with Perl 5

             S - Support Level:
               m   - Mailing-list
               d   - Developer
               u   - Usenet newsgroup comp.lang.perl.modules
               n   - None known, try comp.lang.perl.modules
               a   - abandoned; volunteers welcome to take over maintenance

             L - Language Used:
               p   - Perl-only, no compiler needed, should be platform independent
               c   - C and perl, a C compiler will be needed
               h   - Hybrid, written in perl with optional C code, no compiler needed
               +   - C++ and perl, a C++ compiler will be needed
               o   - perl and another language other than C or C++

             I - Interface Style
               f   - plain Functions, no references used
               h   - hybrid, object and function interfaces available
               n   - no interface at all (huh?)
               r   - some use of unblessed References or ties
               O   - Object oriented using blessed references and/or inheritance

             P - Public License
               p   - Standard-Perl: user may choose between GPL and Artistic
               g   - GPL: GNU General Public License
               l   - LGPL: "GNU Lesser General Public License" (previously known as
                     "GNU Library General Public License")
               b   - BSD: The BSD License
               a   - Artistic license alone
               2   - Artistic license 2.0 or later
               o   - open source: approved by www.opensource.org
               d   - allows distribution without restrictions
               r   - restricted distribution
               n   - no license at all

       CPAN::Module::force($method,@args)
           Forces  CPAN to perform a task it would normally refuse to do. Force takes as arguments a method name
           to be invoked and any number of additional arguments to pass  that  method.   The  internals  of  the
           object  get  the  needed  changes  so  that  CPAN.pm does not refuse to take the action. See also the
           section above on the "force" and the "fforce" pragma.

       CPAN::Module::get()
           Runs a get on the distribution associated with this module.

       CPAN::Module::inst_file()
           Returns the filename of the module found in @INC. The first file found  is  reported,  just  as  perl
           itself stops searching @INC once it finds a module.

       CPAN::Module::available_file()
           Returns  the  filename of the module found in PERL5LIB or @INC. The first file found is reported. The
           advantage of this method over "inst_file" is that modules that have been tested but not yet installed
           are included because PERL5LIB keeps track of tested modules.

       CPAN::Module::inst_version()
           Returns the version number of the installed module in readable format.

       CPAN::Module::available_version()
           Returns the version number of the available module in readable format.

       CPAN::Module::install()
           Runs an "install" on the distribution associated with this module.

       CPAN::Module::look()
           Changes to the directory where the distribution associated with this module  has  been  unpacked  and
           opens a subshell there. Exiting the subshell returns.

       CPAN::Module::make()
           Runs a "make" on the distribution associated with this module.

       CPAN::Module::manpage_headline()
           If  module  is  installed,  peeks  into  the  module's  manpage,  reads the headline, and returns it.
           Moreover, if the module has  been  downloaded  within  this  session,  does  the  equivalent  on  the
           downloaded module even if it hasn't been installed yet.

       CPAN::Module::perldoc()
           Runs a "perldoc" on this module.

       CPAN::Module::readme()
           Runs a "readme" on the distribution associated with this module.

       CPAN::Module::reports()
           Calls the reports() method on the associated distribution object.

       CPAN::Module::test()
           Runs a "test" on the distribution associated with this module.

       CPAN::Module::uptodate()
           Returns 1 if the module is installed and up-to-date.

       CPAN::Module::userid()
           Returns the author's ID of the module.

   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). The contents of this  cache  may
       be  used  for  later  re-installations  that you intend to do manually, but will never be trusted by CPAN
       itself. This is due to the fact that the user  might  use  these  directories  for  building  modules  on
       different architectures.

       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 being  that  one  special  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 (e.g. Foo::Bar, i.e. 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.

       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 which is available in the shell  interface  does  that  for  you  by  including  all
       currently installed modules in a snapshot bundle file.

PREREQUISITES

       The  CPAN  program  is  trying  to  depend  on  as  little  as possible so the user can use it in hostile
       environment. It works better the more goodies the environment provides. For example if  you  try  in  the
       CPAN shell

         install Bundle::CPAN

       or

         install Bundle::CPANxxl

       you will find the shell more convenient than the bare shell before.

       If  you have a local mirror of CPAN and can access all files with "file:" URLs, then you only need a perl
       later than perl5.003 to run this module. Otherwise Net::FTP is strongly recommended. LWP may be  required
       for non-UNIX systems, or if your nearest CPAN site is associated with a URL that is not "ftp:".

       If  you  have  neither  Net::FTP  nor  LWP, there is a fallback mechanism implemented for an external ftp
       command or for an external lynx command.

UTILITIES

   Finding packages and VERSION
       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 far too much memory to load all packages into the running program just to determine
         the $VERSION variable. Currently all programs that are dealing with version use something like this

             perl -MExtUtils::MakeMaker -le \
                 'print MM->parse_version(shift)' 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 and contain a "Makefile.PL" or "Build.PL" (well,
         we try to handle a bit more, but with little enthusiasm).

   Debugging
       Debugging  this  module  is  more  than a bit complex due to interference from the software producing the
       indices on CPAN, the mirroring process on CPAN, packaging, configuration, synchronicity, and even (gasp!)
       due to bugs within the CPAN.pm module itself.

       For debugging the code of CPAN.pm itself in interactive mode, some debugging aid can  be  turned  on  for
       most packages within CPAN.pm with one of

       o debug package...
         sets debug mode for packages.

       o debug -package...
         unsets debug mode for packages.

       o debug all
         turns debugging on for all packages.

       o debug number

       which sets the debugging packages directly. Note that "o debug 0" turns debugging off.

       What  seems  a  successful strategy is the combination of "reload cpan" and the debugging switches. Add a
       new debug statement while running in the shell and then issue a "reload cpan" and see the  new  debugging
       messages immediately without losing the current context.

       "o  debug" without an argument lists the valid package names and the current set of packages in debugging
       mode. "o debug" has built-in completion support.

       For  debugging  of  CPAN  data  there  is  the  "dump"  command  which  takes  the  same   arguments   as
       make/test/install  and outputs each object's Data::Dumper dump. If an argument looks like a perl variable
       and contains one of "$", "@" or "%", it is eval()ed and fed to Data::Dumper directly.

   Floppy, Zip, Offline Mode
       CPAN.pm works nicely without network access, too. If you maintain machines that are not networked at all,
       you should consider working with "file:" URLs. You'll have to collect your modules  somewhere  first.  So
       you   might  use  CPAN.pm  to  put  together  all  you  need  on  a  networked  machine.  Then  copy  the
       $CPAN::Config->{keep_source_where} (but not  $CPAN::Config->{build_dir})  directory  on  a  floppy.  This
       floppy  is  kind of a personal CPAN. CPAN.pm on the non-networked machines works nicely with this floppy.
       See also below the paragraph about CD-ROM support.

   Basic Utilities for Programmers
       has_inst($module)
         Returns true if the module is installed. Used to load all modules into the  running  CPAN.pm  that  are
         considered  optional. The config variable "dontload_list" intercepts the "has_inst()" call such that an
         optional module is not loaded despite being available. For example, the following command will  prevent
         "YAML.pm" from being loaded:

             cpan> o conf dontload_list push YAML

         See the source for details.

       use_inst($module)
         Similary to has_inst() tries to load optional library but also dies if library is not available

       has_usable($module)
         Returns  true  if  the  module is installed and in a usable state. Only useful for a handful of modules
         that are used internally. See the source for details.

       instance($module)
         The constructor for all the singletons used to represent modules, distributions, authors, and  bundles.
         If the object already exists, this method returns the object; otherwise, it calls the constructor.

       frontend()
       frontend($new_frontend)
         Getter/setter for frontend object. Method just allows to subclass CPAN.pm.

SECURITY

       There's  no  strong  security  layer in CPAN.pm. CPAN.pm helps you to install foreign, unmasked, unsigned
       code on your machine. We compare to a checksum that comes from the net  just  as  the  distribution  file
       itself. But we try to make it easy to add security on demand:

   Cryptographically signed modules
       Since  release  1.77, CPAN.pm has been able to verify cryptographically signed module distributions using
       Module::Signature.  The CPAN modules can be signed by their authors,  thus  giving  more  security.   The
       simple  unsigned  MD5  checksums  that  were  used  before by CPAN protect mainly against accidental file
       corruption.

       You will need to have Module::Signature installed, which in turn requires that you have at least  one  of
       Crypt::OpenPGP module or the command-line gpg tool installed.

       You  will  also need to be able to connect over the Internet to the public key servers, like pgp.mit.edu,
       and their port 11731 (the HKP protocol).

       The configuration parameter check_sigs is there to turn signature checking on or off.

EXPORT

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

ENVIRONMENT

       When  the  CPAN shell enters a subshell via the look command, it sets the environment CPAN_SHELL_LEVEL to
       1, or increments that variable if it is already set.

       When CPAN runs, it sets the environment variable PERL5_CPAN_IS_RUNNING to the ID of the running  process.
       It  also  sets  PERL5_CPANPLUS_IS_RUNNING  to  prevent  runaway  processes  which could happen with older
       versions of Module::Install.

       When running "perl Makefile.PL", the environment variable "PERL5_CPAN_IS_EXECUTING" is set  to  the  full
       path  of the "Makefile.PL" that is being executed. This prevents runaway processes with newer versions of
       Module::Install.

       When the config variable ftp_passive is set, all downloads will be  run  with  the  environment  variable
       FTP_PASSIVE  set  to  this  value.  This is in general a good idea as it influences both Net::FTP and LWP
       based connections. The same effect can be achieved by starting  the  cpan  shell  with  this  environment
       variable set. For Net::FTP alone, one can also always set passive mode by running libnetcfg.

POPULATE AN INSTALLATION WITH LOTS OF MODULES

       Populating  a freshly installed perl with one's favorite modules is pretty easy if you maintain a private
       bundle definition file. To get a useful blueprint of a bundle definition file, the command autobundle can
       be used on the CPAN shell command line. This command writes a bundle  definition  file  for  all  modules
       installed for the current perl interpreter. It's recommended to run this command once only, and from then
       on  maintain  the  file manually under a private name, say Bundle/my_bundle.pm. With a clever bundle file
       you can then simply say

           cpan> install Bundle::my_bundle

       then answer a few questions and go out for coffee (possibly even in a different city).

       Maintaining a bundle definition file means keeping track of two things: dependencies  and  interactivity.
       CPAN.pm  sometimes  fails  on  calculating  dependencies  because  not  all  modules define all MakeMaker
       attributes correctly, so a bundle definition file should specify prerequisites as early as  possible.  On
       the  other  hand, it's annoying that so many distributions need some interactive configuring. So what you
       can try to accomplish in your private bundle file is to have the packages  that  need  to  be  configured
       early  in  the file and the gentle ones later, so you can go out for coffee after a few minutes and leave
       CPAN.pm to churn away unattended.

WORKING WITH CPAN.pm BEHIND FIREWALLS

       Thanks to Graham Barr for contributing the following paragraphs about the interaction between  perl,  and
       various  firewall  configurations. For further information on firewalls, it is recommended to consult the
       documentation that comes with the ncftp program. If you are unable to go  through  the  firewall  with  a
       simple Perl setup, it is likely that you can configure ncftp so that it works through your firewall.

   Three basic types of firewalls
       Firewalls can be categorized into three basic types.

       http firewall
           This  is when the firewall machine runs a web server, and to access the outside world, you must do so
           via that web server. If you  set  environment  variables  like  http_proxy  or  ftp_proxy  to  values
           beginning  with  http://,  or in your web browser you've proxy information set, then you know you are
           running behind an http firewall.

           To access servers outside these types of firewalls  with  perl  (even  for  ftp),  you  need  LWP  or
           HTTP::Tiny.

       ftp firewall
           This  where  the  firewall machine runs an ftp server. This kind of firewall will only let you access
           ftp servers outside the firewall.  This is usually done by connecting to the firewall with ftp,  then
           entering a username like "user@outside.host.com".

           To access servers outside these type of firewalls with perl, you need Net::FTP.

       One-way visibility
           One-way  visibility  means  these  firewalls  try  to  make  themselves invisible to users inside the
           firewall. An FTP data connection is normally created by sending your IP address to the remote  server
           and  then  listening  for the return connection. But the remote server will not be able to connect to
           you because of the firewall. For these types of firewall, FTP  connections  need  to  be  done  in  a
           passive mode.

           There are two that I can think off.

           SOCKS
               If  you  are  using  a  SOCKS  firewall, you will need to compile perl and link it with the SOCKS
               library.  This is what is normally called a 'socksified' perl. With this executable you  will  be
               able to connect to servers outside the firewall as if it were not there.

           IP Masquerade
               This is when the firewall implemented in the kernel (via NAT, or networking address translation),
               it  allows  you  to  hide a complete network behind one IP address. With this firewall no special
               compiling is needed as you can access hosts directly.

               For accessing ftp servers behind such firewalls you usually need to set the environment  variable
               "FTP_PASSIVE" or the config variable ftp_passive to a true value.

   Configuring lynx or ncftp for going through a firewall
       If you can go through your firewall with e.g. lynx, presumably with a command such as

           /usr/local/bin/lynx -pscott:tiger

       then you would configure CPAN.pm with the command

           o conf lynx "/usr/local/bin/lynx -pscott:tiger"

       That's all. Similarly for ncftp or ftp, you would configure something like

           o conf ncftp "/usr/bin/ncftp -f /home/scott/ncftplogin.cfg"

       Your mileage may vary...

FAQ

       1)  I installed a new version of module X but CPAN keeps saying, I have the old version installed

           Probably  you  do  have the old version installed. This can happen if a module installs itself into a
           different directory in the @INC path than it was previously installed. This is not really  a  CPAN.pm
           problem,  you  would  have  the  same problem when installing the module manually. The easiest way to
           prevent this behaviour is to add the argument "UNINST=1" to the "make install" call, and that is  why
           many people add this argument permanently by configuring

             o conf make_install_arg UNINST=1

       2)  So why is UNINST=1 not the default?

           Because  there are people who have their precise expectations about who may install where in the @INC
           path and who uses which @INC array. In fine tuned environments "UNINST=1" can cause damage.

       3)  I want to clean up my mess, and install a new perl along with all modules I have. How do I  go  about
           it?

           Run  the  autobundle  command for your old perl and optionally rename the resulting bundle file (e.g.
           Bundle/mybundle.pm), install the new perl with the Configure option prefix, e.g.

               ./Configure -Dprefix=/usr/local/perl-5.6.78.9

           Install the bundle file you produced in the first step with something like

               cpan> install Bundle::mybundle

           and you're done.

       4)  When I install bundles or multiple modules with one command there is too much output  to  keep  track
           of.

           You may want to configure something like

             o conf make_arg "| tee -ai /root/.cpan/logs/make.out"
             o conf make_install_arg "| tee -ai /root/.cpan/logs/make_install.out"

           so that STDOUT is captured in a file for later inspection.

       5)  I am not root, how can I install a module in a personal directory?

           As  of  CPAN  1.9463,  if  you  do not have permission to write the default perl library directories,
           CPAN's configuration process will ask you whether you want to  bootstrap  <local::lib>,  which  makes
           keeping a personal perl library directory easy.

           Another  thing  you  should  bear  in mind is that the UNINST parameter can be dangerous when you are
           installing into a private area because you might accidentally remove modules that other people depend
           on that are not using the private area.

       6)  How to get a package, unwrap it, and make a change before building it?

           Have a look at the "look" (!) command.

       7)  I installed a Bundle and had a couple of fails. When I retried, everything resolved nicely. Can  this
           be fixed to work on first try?

           The reason for this is that CPAN does not know the dependencies of all modules when it starts out. To
           decide  about  the  additional  items to install, it just uses data found in the META.yml file or the
           generated Makefile. An undetected missing piece breaks the process. But it  may  well  be  that  your
           Bundle  installs some prerequisite later than some depending item and thus your second try is able to
           resolve everything.  Please note, CPAN.pm does not know the dependency tree  in  advance  and  cannot
           sort  the  queue of things to install in a topologically correct order. It resolves perfectly well if
           all modules declare the prerequisites correctly with the PREREQ_PM  attribute  to  MakeMaker  or  the
           "requires"  stanza  of  Module::Build.  For  bundles  which fail and you need to install often, it is
           recommended to sort the Bundle definition file manually.

       8)  In our intranet, we have many modules for internal use.  How  can  I  integrate  these  modules  with
           CPAN.pm but without uploading the modules to CPAN?

           Have a look at the CPAN::Site module.

       9)  When  I  run CPAN's shell, I get an error message about things in my "/etc/inputrc" (or "~/.inputrc")
           file.

           These are readline issues  and  can  only  be  fixed  by  studying  readline  configuration  on  your
           architecture   and   adjusting  the  referenced  file  accordingly.  Please  make  a  backup  of  the
           "/etc/inputrc" or "~/.inputrc" and edit them.  Quite  often  harmless  changes  like  uppercasing  or
           lowercasing some arguments solves the problem.

       10) Some authors have strange characters in their names.

           Internally  CPAN.pm  uses  the  UTF-8  charset.  If  your terminal is expecting ISO-8859-1 charset, a
           converter can be activated by setting term_is_latin to a true value in your config file. One  way  of
           doing so would be

               cpan> o conf term_is_latin 1

           If  other  charset  support  is  needed,  please file a bug report against CPAN.pm at rt.cpan.org and
           describe your needs. Maybe we  can  extend  the  support  or  maybe  UTF-8  terminals  become  widely
           available.

           Note:  this config variable is deprecated and will be removed in a future version of CPAN.pm. It will
           be replaced with the conventions around the family of $LANG and $LC_* environment variables.

       11) When an install fails for some reason and then I correct  the  error  condition  and  retry,  CPAN.pm
           refuses to install the module, saying "Already tried without success".

           Use the force pragma like so

             force install Foo::Bar

           Or you can use

             look Foo::Bar

           and then "make install" directly in the subshell.

       12) How do I install a "DEVELOPER RELEASE" of a module?

           By  default, CPAN will install the latest non-developer release of a module. If you want to install a
           dev release, you have to specify the partial path starting with the author id to the tarball you wish
           to install, like so:

               cpan> install KWILLIAMS/Module-Build-0.27_07.tar.gz

           Note that you can use the "ls" command to get this path listed.

       13) How do I install a module and all its dependencies from the commandline, without being  prompted  for
           anything, despite my CPAN configuration (or lack thereof)?

           CPAN  uses  ExtUtils::MakeMaker's  prompt()  function  to  ask  its  questions,  so  if  you  set the
           PERL_MM_USE_DEFAULT environment variable, you shouldn't be asked any questions at all  (assuming  the
           modules you are installing are nice about obeying that variable as well):

               % PERL_MM_USE_DEFAULT=1 perl -MCPAN -e 'install My::Module'

       14) How  do  I  create  a  Module::Build  based  Build.PL  derived  from  an  ExtUtils::MakeMaker focused
           Makefile.PL?

           http://search.cpan.org/dist/Module-Build-Convert/

       15) I'm frequently irritated with the CPAN shell's inability to help me select a good mirror.

           CPAN can now help you select a "good" mirror, based on which ones have the lowest  'ping'  round-trip
           times.   From the shell, use the command 'o conf init urllist' and allow CPAN to automatically select
           mirrors for you.

           Beyond that help, the urllist config parameter is yours. You can add and remove sites  at  will.  You
           should  find  out  which  sites  have  the  best up-to-dateness, bandwidth, reliability, etc. and are
           topologically close to  you.  Some  people  prefer  fast  downloads,  others  up-to-dateness,  others
           reliability.  You decide which to try in which order.

           Henk P. Penning maintains a site that collects data about CPAN sites:

             http://mirrors.cpan.org/

           Also, feel free to play with experimental features. Run

             o conf init randomize_urllist ftpstats_period ftpstats_size

           and  choose your favorite parameters. After a few downloads running the "hosts" command will probably
           assist you in choosing the best mirror sites.

       16) Why do I get asked the same questions every time I start the shell?

           You can  make  your  configuration  changes  permanent  by  calling  the  command  "o  conf  commit".
           Alternatively  set  the  "auto_commit"  variable  to  true  by  running "o conf init auto_commit" and
           answering the following question with yes.

       17) Older versions of CPAN.pm had the original root directory of all tarballs in the build directory. Now
           there are always random characters appended to these directory names. Why was this done?

           The random characters are provided by File::Temp and  ensure  that  each  module's  individual  build
           directory is unique. This makes running CPAN.pm in concurrent processes simultaneously safe.

       18) Speaking of the build directory. Do I have to clean it up myself?

           You  have  the  choice  to set the config variable "scan_cache" to "never". Then you must clean it up
           yourself. The other possible values, "atstart" and "atexit" clean up the  build  directory  when  you
           start  (or  more  precisely,  after  the  first extraction into the build directory) or exit the CPAN
           shell, respectively. If you never start up the CPAN shell, you probably also have  to  clean  up  the
           build directory yourself.

       19) How can I switch to sudo instead of local::lib?

           The  following  5  environment  veriables  need  to  be reset to the previous values: PATH, PERL5LIB,
           PERL_LOCAL_LIB_ROOT, PERL_MB_OPT, PERL_MM_OPT;  and  these  two  CPAN.pm  config  variables  must  be
           reconfigured: make_install_make_command and mbuild_install_build_command. The five env variables have
           probably  been  overwritten  in your $HOME/.bashrc or some equivalent. You either find them there and
           delete their traces and logout/login or you  override  them  temporarily,  depending  on  your  exact
           desire. The two cpanpm config variables can be set with:

             o conf init /install_.*_command/

           probably followed by

             o conf commit

COMPATIBILITY

   OLD PERL VERSIONS
       CPAN.pm  is  regularly tested to run under 5.005 and assorted newer versions. It is getting more and more
       difficult to get the minimal prerequisites working on older perls. It is close to impossible to  get  the
       whole  Bundle::CPAN  working there. If you're in the position to have only these old versions, be advised
       that CPAN is designed to work fine without the Bundle::CPAN installed.

       To get things going, note that GBARR/Scalar-List-Utils-1.18.tar.gz is compatible with ancient  perls  and
       that File::Temp is listed as a prerequisite but CPAN has reasonable workarounds if it is missing.

   CPANPLUS
       This  module  and  its  competitor,  the CPANPLUS module, are both much cooler than the other. CPAN.pm is
       older. CPANPLUS was designed to be more modular, but it was never intended to be compatible with CPAN.pm.

   CPANMINUS
       In the year 2010 App::cpanminus was launched as a new approach  to  a  cpan  shell  with  a  considerably
       smaller footprint. Very cool stuff.

SECURITY ADVICE

       This software enables you to upgrade software on your computer and so is inherently dangerous because the
       newly  installed  software  may  contain  bugs  and may alter the way your computer works or even make it
       unusable. Please consider backing up your data before every upgrade.

BUGS

       Please report bugs via <http://rt.cpan.org/>

       Before submitting a bug, please make sure that the traditional method of building a Perl  module  package
       from a shell by following the installation instructions of that package still works in your environment.

AUTHOR

       Andreas Koenig "<andk@cpan.org>"

LICENSE

       This  program  is  free  software;  you can redistribute it and/or modify it under the same terms as Perl
       itself.

       See <http://www.perl.com/perl/misc/Artistic.html>

TRANSLATIONS

       Kawai,Takanori  provides  a  Japanese  translation  of  a  very  old   version   of   this   manpage   at
       <http://homepage3.nifty.com/hippo2000/perltips/CPAN.htm>

SEE ALSO

       Many  people  enter  the  CPAN  shell  by running the cpan utility program which is installed in the same
       directory as perl itself. So if you have this directory in your PATH variable (or some equivalent in your
       operating system) then typing "cpan" in a console window will work  for  you  as  well.  Above  that  the
       utility provides several commandline shortcuts.

       The   main   CPAN   website,   which   includes   general   information   about   the   service,   is  at
       <http://www.cpan.org/>.

       melezhik  (Alexey)  sent  me  a  link  where  he  published  a  chef  recipe  to   work   with   CPAN.pm:
       http://community.opscode.com/cookbooks/cpan.

perl v5.34.0                                       2025-04-08                                        CPAN(3perl)