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


cpanm Module

Run cpanm -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 less than 10MB RAM. See below for its cons.


cpan> install App::cpanminus


cd ~/bin wget chmod +x cpanm

edit shebang if you don't have /usr/bin/env


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?

Probably not. You should use CPAN or CPANPLUS.

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. I hope (and have talked to) QA/toolchain people building a queriable CPAN DB website so I can stop scraping.

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

Yet Another CPAN installer? Are you on drugs?

Yes, I think my brain has been damaged since I looked at PyPI, gemcutter, pip and rip. They're quite nice.

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 outdated and cannot be resurrected, Bundle:: modules, circular dependencies etc.) while CPAN and CPANPLUS can handle them.

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

Not really. 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.

That sounds fantastic. Should I switch to this from CPAN(PLUS)?

While I think you should really use CPAN or CPANPLUS in the longer term, I'm happy if you like this software. And apparently, many people love (at least the idea of) this software :)


Copyright 2010- Tatsuhiko Miyagawa

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


Same as Perl.


Patches contributed by: Goro Fuji, Kazuhiro Osawa, Tokuhiro Matsuno, Kenichi Ishigaki, Ian Wells, Pedro Melo.

Feedbacks sent by: Jesse Vincent, David Golden, Chris Williams, Matt S Trout, Adam Kennedy.


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.