CPAN(3perl) - phpMan

CPAN(3perl) Perl Programmers Reference Guide CPAN(3perl)

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

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/

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

o pass additional arguments to one of the four commands,

o set environment variables

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

o temporarily override assorted "CPAN.pm" configuration variables

o specify dependencies the original maintainer forgot

o 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

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

o 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.

o 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 AT outside.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 AT 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 2023-11-23 CPAN(3perl)

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