cpanminus - get, unpack, build and install modules from CPAN


    cpanm Module

Run cpan -h for more options.


cpanminus is a script to get, unpack, build and install modules from CPAN.

Its catch? Deps-free, zero-conf, standalone ~200 LOC script (i.e. hackable) and requires only 10MB RAM. See below for its cons.


Grab the file from, chmod +x, put it into your PATH. Adjust shebang if needed.


perl 5.8 or later (Actually I believe it works with pre 5.8 too but haven't tested).

  • LWP or 'wget' to get files over HTTP.

  • 'tar' executable or Archive::Tar to unpack files.

  • C compiler, if you want to build XS modules.

And optionally:

  • make, if you want to more reliably install MakeMaker based modules

  • Module::Build (core in 5.10) if you want to install MakeMaker based modules without 'make'


Should I really use this?


WTF? What's the point?

OK, the first motivation was this: CPAN shell gets OOM (or swaps heavily and gets really slow) on Slicehost/linode's most affordable plan with only 256MB RAM. Should I pay more to install perl modules from CPAN? I don't think so.

Yes, I know there are tools like CPAN::SQLite that can fix that problem (and yes I use it on my Macbook Pro!) but installing it and its 14 non-core dependencies without CPAN shell (because CPAN shell doesn't work) feels like yak shaving.

So, imagine you don't have CPAN or CPANPLUS. What you're going to do is to search the module on the CPAN search site, download a tarball, unpack it and then run perl Makefile.PL (or perl Build.PL) and then make install (or ./Build install). If the module has dependencies you probably have to recurively resolve those dependencies by hand before doing so.

This script just automates that.

Zero-conf? How does this module get/parse/update the CPAN index?

It scrapes the site Yes, it's horrible and fragile.

Fetched files are unpacked in ~/.cpanm but you can configure with CPANMINUS_HOME environment variable.

Are you on drugs?

Yes, I think my brain has been damaged since I looked at PyPI, gemcutter, pip and rip.

Where does this install modules to?

It installs to wherever ExtUtils::MakeMaker and Module::Build are configured to (i.e. via PERL_MM_OPT and MODULEBUILDRC). So if you use local::lib then it installs to your local perl5 directory. Otherwise it installs to siteperl directory, so you might need to run cpanm command as root, or run with --sudo option to auto sudo when running the install command.

Does this really work?

I tested installing MojoMojo, KiokuDB, Catalyst, Jifty and Plack using cpanminus and the installations including dependencies were mostly successful. So multiplies of half of CPAN behave really nicely and appear to work.

However, there are some distributions that will miserably fail, because of the nasty edge cases (funky archive formats, naughty tarball that extracts to the current directory, META.yml that is outdatd, META.yml that is not really YAML, circular dependencies etc.) while CPAN and CPANPLUS can handle them.

Quick Install?

    env PERL_MM_USE_DEFAULT=1 cpanm --notest Module

Oh, don't do that. It's too useful.

So you're ignoring the CPAN toolchain ecosystem with this?

No, that's not my intention. This tiny script actually respects and plays nice with all the toolchain ecosystem that has been developed for years, such as: Module::Build, Module::Install, ExtUtils::MakeMaker and local::lib. It just provides an alternative to (but NOT a replacement for) CPAN or CPANPLUS, so that it doesn't require any configuration, any dependencies and has no bootstrap problems.

The thing is, I've learned that often for less experienced users, or even really experienced users who knows how to shoot in their feet, setting up a CPAN toolchain in the right way feels like just another yak to shave when all they want to do is just to quickstart writing perl code by installing CPAN modules. cpanminus is a super tiny shaver to eliminate the big yak really quickly in that case, and does nothing else.

Should I really use this?



Copyright 2010- Tatsuhiko Miyagawa

Parse::CPAN::Meta, included in this script, is Copyright 2006-2009 Adam Kennedy


Same as Perl.


Tatsuhiko Miyagawa, Goro Fuji, Kazuhiro Osawa, Tokuhiro Matsuno, Ken-ichi Ishigaki, Ian Wells


This software is provided "as-is," without any express or implied warranty. In no event shall the author be held liable for any damages arising from the use of the software.