Package management system

There are Debian packages, RPMs, FreeBSD ports, and packages for other operation systems available. If you want to use the package management system, search for cpanminus and use the appropriate command to install. This makes it easy to install "cpanm" to your system without thinking about where to install, and later upgrade.

Installing to system perl

You can also use the latest cpanminus to install cpanminus itself:

curl -L https://cpanmin.us | perl - --sudo App::cpanminus

This will install "cpanm" to your bin directory like "/usr/local/bin" and you'll need the "--sudo" option to write to the directory, unless you configured "INSTALL_BASE" with local::lib.

Installing to local perl (perlbrew, plenv etc.)

If you have perl in your home directory, which is the case if you use tools like perlbrew or plenv, you don't need the "--sudo" option, since you're most likely to have a write permission to the perl's library path. You can just do:

curl -L https://cpanmin.us | perl - App::cpanminus

to install the "cpanm" executable to the perl's bin path, like "~/perl5/perlbrew/bin/cpanm".

Downloading the standalone executable

You can also copy the standalone executable to whatever location you'd like.

cd ~/bin
curl -L https://cpanmin.us/ -o cpanm
chmod +x cpanm

This just works, but be sure to grab the new version manually when you upgrade because "--self-upgrade" might not work with this installation setup.

Troubleshoot: HTTPS warnings

When you run "curl" commands above, you may encounter SSL handshake errors or certification warnings. This is due to your HTTP client (curl) being old, or SSL certificates installed on your system needs to be updated.

You're recommended to update the software or system if you can. If that is impossible or difficult, use the "-k" option with curl.

How does cpanm get/parse/update the CPAN index?

It queries the CPAN Meta DB site at http://cpanmetadb.plackperl.org/. The site is updated at least every hour to reflect the latest changes from fast syncing mirrors. The script then also falls back to query the module at http://metacpan.org/ using its search API.

Upon calling these API hosts, cpanm (1.6004 or later) will send the local perl versions to the server in User-Agent string by default. You can turn it off with "--no-report-perl-version" option. Read more about the option with cpanm, and read more about the privacy policy about this data collection at http://cpanmetadb.plackperl.org/#privacy

Fetched files are unpacked in "~/.cpanm" and automatically cleaned up periodically. You can configure the location of this with the "PERL_CPANM_HOME" environment variable.

Where does this install modules to? Do I need root access?

It installs to wherever ExtUtils::MakeMaker and Module::Build are configured to (via "PERL_MM_OPT" and "PERL_MB_OPT").

By default, it installs to the site_perl directory that belongs to your perl. You can see the locations for that by running "perl -V" and it will be likely something under "/opt/local/perl/..." if you're using system perl, or under your home directory if you have built perl yourself using perlbrew or plenv.

If you've already configured local::lib on your shell, cpanm respects that settings and modules will be installed to your local perl5 directory.

At a boot time, cpanminus checks whether you have already configured local::lib, or have a permission to install modules to the site_perl directory. If neither, i.e. you're using system perl and do not run cpanm as a root, it automatically sets up local::lib compatible installation path in a "perl5" directory under your home directory.

To avoid this, run "cpanm" either as a root user, with "--sudo" option, or with "--local-lib" option.

cpanminus can't install the module XYZ. Is it a bug?

It is more likely a problem with the distribution itself. cpanminus doesn't support or may have issues with distributions such as follows:

• Tests that require input from STDIN.
• Build.PL or Makefile.PL that prompts for input even when "PERL_MM_USE_DEFAULT" is enabled.
• Modules that have invalid numeric values as VERSION (such as "1.1a")

These failures can be reported back to the author of the module so that they can fix it accordingly, rather than to cpanminus.

Does cpanm support the feature XYZ of CPAN and CPANPLUS?

Most likely not. Here are the things that cpanm doesn't do by itself.

If you need these features, use CPAN, CPANPLUS or the standalone tools that are mentioned.

• CPAN testers reporting. See App::cpanminus::reporter
• Building RPM packages from CPAN modules
• Listing the outdated modules that needs upgrading. See App::cpanoutdated
• Showing the changes of the modules you're about to upgrade. See cpan-listchanges
• Patching CPAN modules with distroprefs.

See cpanm or "cpanm -h" to see what cpanminus can do :)

CONTRIBUTORS

Patches and code improvements were contributed by:

Goro Fuji, Kazuhiro Osawa, Tokuhiro Matsuno, Kenichi Ishigaki, Ian Wells, Pedro Melo, Masayoshi Sekimura, Matt S Trout (mst), squeeky, horus and Ingy dot Net.

ACKNOWLEDGEMENTS

Bug reports, suggestions and feedbacks were sent by, or general acknowledgement goes to:

Jesse Vincent, David Golden, Andreas Koenig, Jos Boumans, Chris Williams, Adam Kennedy, Audrey Tang, J. Shirley, Chris Prather, Jesse Luehrs, Marcus Ramberg, Shawn M Moore, chocolateboy, Chirs Nehren, Jonathan Rockway, Leon Brocard, Simon Elliott, Ricardo Signes, AEvar Arnfjord Bjarmason, Eric Wilhelm, Florian Ragwitz and xaicron.