App::cpanminus

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 http://cpanmin.us | perl - --sudo App::cpanminus

This will install "cpanm" to your bin directory like "/usr/local/bin" (unless you configured "INSTALL_BASE" with local::lib), so you probably need the "--sudo" option.

Installing to local perl (perlbrew)

If you have perl in your home directory, which is the case if you use tools like perlbrew, 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 http://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 -LO http://xrl.us/cpanm
    chmod +x cpanm
    # edit shebang if you don't have /usr/bin/env

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

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, let me be clear that CPAN and CPANPLUS are 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.

Zero-conf? How does this module 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 wonderful 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"). So if you're using local::lib, then it installs to your local perl5 directory. Otherwise it installs to the site_perl directory that belongs to your perl.

cpanminus at a boot time checks whether you have configured local::lib, or have the permission to install modules to the site_perl 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, 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 is known to have issues with distributions like as follows:

• Tests that require input from STDIN.
• Tests that might fail when "AUTOMATED_TESTING" 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 me.

Does cpanm support the feature XYZ of CPAN and CPANPLUS?

Most likely not. Here are the things that cpanm doesn't do by itself. And it's a feature - you got that from the name minus, right?

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.