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App::cpanminus - get, unpack, build and install modules from CPAN
cpanm Module
cpanm MIYAGAWA/Plack-1.0000.tar.gz
cpanm ~/mydists/MyCompany-Framework-1.0.tar.gz
cpanm --interactive Task::Kensho
Run `cpanm -h' for more options.
cpanminus is a script to get, unpack, build and install modules from
Why? It's dependency free, requires zero configuration, and stands alone
-- but it's maintainable and extensible with plugins and friendly to
shell scripting. When running, it requires only 10MB of RAM.
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.
If you want to build the latest from source,
git clone git://
cd cpanminus
perl Makefile.PL
make install # or sudo make install if you're non root
This will install `cpanm' to your bin directory like `/usr/local/bin'
(unless you configured `INSTALL_BASE' with local::lib), so you might
need to sudo. Later you can say `cpanm --self-upgrade --sudo' to upgrade
to the latest version.
cd ~/bin
chmod +x cpanm
# edit shebang if you don't have /usr/bin/env
just works, but be sure to grab the new version manually when you
upgrade (`--self-upgrade' might not work).
perl 5.8 or later (Actually I believe it works with pre 5.8 too but I
haven't tested this).
* 'tar' executable (bsdtar or GNU tar version 1.22 are rcommended) or
Archive::Tar to unpack files.
* C compiler, if you want to build XS modules.
And optionally:
* make, if you want to reliably install MakeMaker based modules
* Module::Build (core in 5.10) to install Build.PL based modules
WARNING: plugin API is not stable so this feature is turned off by
default for now. To enable plugins you have to be savvy enough to look
at the build.log or read the source code to see how :)
The cpanminus core is a compact and simple 1000 lines of code (with some
embedded utilities and documents) but can be extended by writing
plugins. Plugins are flat perl scripts placed inside `~/.cpanm/plugins'.
You can copy (or symlink, if you're a developer) a plugin file to the
directory to enable plugins. Delete the file or symlink to disable it.
See the `plugins/' directory in the git repository for the list of available and
sample plugins.
Another CPAN installer?
OK, the first motivation was this: the CPAN shell runs out of memory (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.
But why a new client?
First of all, I have no intention to dis CPAN or CPANPLUS developers.
Don't get me wrong. They're great tools I've used for *literally* years
(you know how many modules I have on CPAN, right?). I really respect
their efforts of maintaining the most important tools in the CPAN
toolchain ecosystem.
However, for less experienced users (mostly from outside the Perl
community), or even really experienced Perl developers who know how to
shoot themselves in their feet, setting up the CPAN toolchain often
feels like yak shaving, especially when all they want to do is just
install some modules and start writing code.
In particular, here are the few issues I've observed:
* They ask too many questions and do not provide enough sane defaults.
A normal user doesn't (and shouldn't have to) know what's the right
answer for the question `Parameters for the 'perl Build.PL' command?
* They provide very noisy output by default.
* They fetches and rebuild their indexes almost every day, and this
takes time.
* ... and they hog 200MB of memory and thrashes/OOMs on my 256MB VPS
cpanminus is designed to be very quiet (but logs all output to
`~/.cpanm/build.log') and to pick the sanest possibledefaults without
asking any questions -- to *just work*.
Note that most of these problems with existing tools are rare, or are
just overstated. They might already be fixed, or can be configured to
work nicer. For instance, the latest dev release has a much
better first time configuration experience than ever before.
I know there's a reason for them to have many options and questions,
because they're meant to work everywhere for everybody.
Of course I should have contributed back to CPAN/CPANPLUS instead of
writing a new client, but is nearly impossible (for anyone other
than andk or xdg) to maintain (that's why CPANPLUS was born, right?) and
CPANPLUS is a huge beast for me to start working on.
Are you on drugs?
Yeah, I think my brain has been damaged since I looked at PyPI,
gemcutter, pip and rip. They're quite nice and I really wanted something
as nice for CPAN which I love.
How does this thing work?
Imagine you don't have CPAN or CPANPLUS. You search for a module on the
CPAN search site, download a tarball, unpack it and then run `perl
Makefile.PL' (or `perl Build.PL'). If the module has dependencies you
probably have to resolve those dependencies by hand before doing so.
Then you run the unit tests and `make install' (or `./Build install').
cpanminus automates that.
Zero-conf? How does this module get/parse/update the CPAN index?
It queries the CPAN Meta DB site running on Google AppEngine at The site is updated every hour to
reflect the latest changes from fast syncing mirrors. The script then
also falls back to the site I've been talking
to and working with with the QA/toolchain people for building a more
reliable CPAN DB website.
Fetched files are unpacked in `~/.cpanm'. You can configure 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 `MODULEBUILDRC'). So if you're
using local::lib, then it installs to your local perl5 directory.
Otherwise it installs to the siteperl directory.
cpanminus at a boot time checks whether you have configured local::lib,
or have the permission to install modules to the sitelib directory. If
neither, it automatically sets up local::lib compatible installation
path in a `perl5' directory under your home directory. To avoid this,
run the script as the root user or with `--sudo' option.
This local::lib automatic integration is still considered alpha and in
the work -- more bootstrapping is under development. Stay tuned.
Does this really work?
I tested installing MojoMojo, Task::Kensho, KiokuDB, Catalyst, Jifty and
Plack using cpanminus and the installations including dependencies were
mostly successful. More than *half of CPAN* behaves really nicely and
appears to work.
However, there might be some distributions that will miserably fail,
because of nasty edge cases. Here are some examples:
* Packages uploaded to PAUSE in 90s which don't live under the
standard `authors/id/A/AA' directory hierarchy.
* Distributions with a `Makefile.PL' or `Build.PL' that asks you
questions without using `prompt' function. However cpanminus has a
mechanism to kill those questions with a timeout, and you can always
say `--interactive' to make the configuration interactive.
* Distributions that do not shipped with `META.yml' file but do
require some specific version of toolchain for configuration.
* Distributions that test a SIGNATURE in the `*.t' unit tests and has
`MANIFEST.SKIP' file in the distribution at the same time. The
intent of signature testing is to provide some degree of security,
but running it in unit tests is too late as it occurs *after*
running `Makefile.PL'. cpanminus has a `verify_signature' plugin to
verify the dist before configurations.
* Distributions that have a `META.yml' file that is encoded in YAML
1.1 format using YAML::XS. This will be eventually solved once we
move to `META.json'.
cpanminus intends to work for 99.9% of modules on CPAN for 99.9% of
people. It may not be perfect, but it should just work in most cases.
If this tool doesn't work for your very rare environment, then I'm
sorry, but you should use CPAN or CPANPLUS, or build and install modules
That sounds fantastic. Should I switch to this from CPAN(PLUS)?
If you have CPAN or CPANPLUS working then you may want to keep using
CPAN or CPANPLUS in the longer term, but I hope this can be a quite
handy alternative to them for people in other situations. And
apparently, many people love (at least the idea of) this software :)
Copyright 2010- Tatsuhiko Miyagawa
The standalone executable contains the following modules embedded.
Parse::CPAN::Meta Copyright 2006-2009 Adam Kennedy
local::lib Copyright 2007-2009 Matt S Trout
HTTP::Lite Copyright 2000-2002 Roy Hopper, 2009 Adam Kennedy
Same as Perl.
Patches and code improvements were contributed by:
Goro Fuji, Kazuhiro Osawa, Tokuhiro Matsuno, Kenichi Ishigaki, Ian
Wells, Pedro Melo, Masayoshi Sekimura, Matt S Trout, squeeky, horus and
Ingy dot Net.
Bug reports, suggestions and feedbacks were sent by, or general
acknowledgement goes to:
Jesse Vincent, David Golden, Andreak 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.
COMMUNITY - source code repository, issue
irc: - discussions about Perl toolchain. I'm there.
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.
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