CPAN(1) Perl Programmers Reference Guide CPAN(1)
cpan - easily interact with CPAN from the command line
# with arguments and no switches, installs specified modules
cpan module_name [ module_name ... ]
# with switches, installs modules with extra behavior
cpan [-cfgimtTw] module_name [ module_name ... ]
# with just the dot, install from the distribution in the
# current directory
# without arguments, starts CPAN.pm shell
# force install modules (usually those that fail tests)
cpan -f module_name [ module_name ... ]
# install modules but without testing them
cpan -T module_name [ module_name ... ]
# dump the configuration
# load a different configuration to install Module::Foo
cpan -j some/other/file Module::Foo
# without arguments, but some switches
This script provides a command interface (not a shell) to CPAN. At the
moment it uses CPAN.pm to do the work, but it is not a one-shot command
runner for CPAN.pm.
-a Creates a CPAN.pm autobundle with CPAN::Shell->autobundle.
-A module [ module ... ]
Shows the primary maintainers for the specified modules.
Runs a `make clean` in the specified module's directories.
-C module [ module ... ]
Show the Changes files for the specified modules
-D module [ module ... ]
Show the module details.
-f Force the specified action, when it normally would have failed. Use
this to install a module even if its tests fail. When you use this
option, -i is not optional for installing a module when you need to
% cpan -f -i Module::Foo
-F Turn off CPAN.pm's attempts to lock anything. You should be careful
with this since you might end up with multiple scripts trying to
muck in the same directory. This isn't so much of a concern if
you're loading a special config with "-j", and that config sets up
its own work directories.
-g module [ module ... ]
Downloads to the current directory the latest distribution of the
-G module [ module ... ]
Download to the current directory the latest distribution of the
modules, unpack each distribution, and create a git repository for
If you want this feature, check out Yanick Champoux's
-h Print a help message and exit. When you specify "-h", it ignores
all of the other options and arguments.
-i Install the specified modules.
-I Load "local::lib" (think like "-I" for loading lib paths).
Load the file that has the CPAN configuration data. This should
have the same format as the standard CPAN/Config.pm file, which
defines $CPAN::Config as an anonymous hash.
-J Dump the configuration in the same format that CPAN.pm uses. This
is useful for checking the configuration as well as using the dump
as a starting point for a new, custom configuration.
-l List all installed modules with their versions
-L author [ author ... ]
List the modules by the specified authors.
-m Make the specified modules.
-O Show the out-of-date modules.
-p Ping the configured mirrors
-P Find the best mirrors you could be using (but doesn't configure
them just yet)
-r Recompiles dynamically loaded modules with CPAN::Shell->recompile.
-t Run a `make test` on the specified modules.
-T Do not test modules. Simply install them.
-u Upgrade all installed modules. Blindly doing this can really break
things, so keep a backup.
-v Print the script version and CPAN.pm version then exit.
-V Print detailed information about the cpan client.
Turn on cpan warnings. This checks various things, like directory
permissions, and tells you about problems you might have.
# print a help message
# print the version numbers
# create an autobundle
# recompile modules
# upgrade all installed modules
# install modules ( sole -i is optional )
cpan -i Netscape::Booksmarks Business::ISBN
# force install modules ( must use -i )
cpan -fi CGI::Minimal URI
There are several components in CPAN.pm that use environment
variables. The build tools, ExtUtils::MakeMaker and Module::Build
use some, while others matter to the levels above them. Some of
these are specified by the Perl Toolchain Gang:
"cpan" splits this variable on whitespace and prepends that
list to @ARGV before it processes the command-line arguments.
For instance, if you always want to use "local:lib", you can
set "CPAN_OPTS" to "-I".
The log level to use, with either the embedded, minimal logger
or Log::Log4perl if it is installed. Possible values are the
same as the "Log::Log4perl" levels: "TRACE", "DEBUG", "INFO",
"WARN", "ERROR", and "FATAL". The default is "INFO".
The path to the "git" binary to use for the Git features. The
default is "/usr/local/bin/git".
Assume no one is paying attention and skips prompts for
distributions that do that correctly. cpan(1) sets this to 1
unless it already has a value (even if that value is false).
Use the default answer for a prompted questions. cpan(1) sets
this to 1 unless it already has a value (even if that value is
The script exits with zero if it thinks that everything worked, or a
positive number if it thinks that something failed. Note, however, that
in some cases it has to divine a failure by the output of things it
does not control. For now, the exit codes are vague:
1 An unknown error
2 The was an external problem
4 There was an internal problem with the script
8 A module failed to install
* one shot configuration values from the command line
* none noted
Most behaviour, including environment variables and configuration,
comes directly from CPAN.pm.
This code is in Github in the CPAN.pm repository:
The source used to be tracked separately in another GitHub repo, but
the canonical source is now in the above repo.
Japheth Cleaver added the bits to allow a forced install (-f).
Jim Brandt suggest and provided the initial implementation for the up-
to-date and Changes features.
Adam Kennedy pointed out that exit() causes problems on Windows where
this script ends up with a .bat extension
brian d foy, "<email@example.com>"
Copyright (c) 2001-2014, brian d foy, All Rights Reserved.
You may redistribute this under the same terms as Perl itself.
perl v5.22.1 2020-10-19 CPAN(1)
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