How can I use CPAN as a non-root user?
The easiest method I have found so far is to say
wget -O- http://cpanmin.us | perl - -l ~/perl5 App::cpanminus local::lib
eval `perl -I ~/perl5/lib/perl5 -Mlocal::lib`
echo 'eval `perl -I ~/perl5/lib/perl5 -Mlocal::lib`' >> ~/.profile
echo 'export MANPATH=$HOME/perl5/man:$MANPATH' >> ~/.profile
This assumes your profile is named .profile, you may need to change that to be .bash_profile, .bashrc, etc. After that you can install modules by saying
cpanm Module::Name
and simply use them the same way you would if the were installed in the root directories.
What follows is a brief explanation of what the commands above do.
wget -O- http://cpanmin.us fetches the latest version of cpanm and prints it to STDOUT which is then piped to perl - -l ~/perl5 App::cpanminus local::lib. The first - tells perl to expect the program to come in on STDIN, this makes perl run the version of cpanm we just downloaded. perl passes the rest of the arguments to cpanm. The -l ~/perl5 argument tells cpanm where to install Perl modules, and the other two arguments are two modules to install. [App::cpanmins]1 is the package that installs cpanm. local::lib is a helper module that manages the environment variables needed to run modules in local directory.
After those modules are installed we run
eval `perl -I ~/perl5/lib/perl5 -Mlocal::lib`
to set the environment variables needed to use the local modules and then
echo 'eval `perl -I ~/perl5/lib/perl5 -Mlocal::lib`' >> ~/.profile
to ensure we will be able to use them the next time we log in.
echo 'export MANPATH=$HOME/perl5/man:$MANPATH' >> ~/.profile
will hopefully cause man to find the man pages for your local modules.
If you want to be able to read man pages for the cpanminus-installed modules as well, you should also make sure the correct subdirectory of the chosen library path is in MANPATH. So the above solution showing the installation process of cpanm needs the following additional command:
export MANPATH=$HOME/Library/perl5/man:$MANPATH' >> ~/.bash_profile
http://web.archive.org/web/20120427144232/http://perl.jonallen.info/writing/articles/install-perl-modules-without-root
http://novosial.org/perl/life-with-cpan/non-root/
The main step in both sets of instructions involves local::lib module
AFAIK, CPAN logic is contained in Perl module (CPAN.pm) which means you can also easily install the newer one in your local directory as you would with any other Perl module.
Also, once you install your modules in non-standard location, check out these two questions on loading libraries from non-standard locations (some of the info is already available in the link above):
How does a Perl program know where to find the file containing Perl module it uses?
How is Perl’s @INC constructed? (aka What are all the ways of affecting where Perl modules are searched for?)
For completeness, this is the installation process of cpanm on OSX if you want to keep your perl5 under ~/Library.
curl -L http://cpanmin.us | perl - -l ~/Library/perl5 App::cpanminus local::lib
eval `perl -I ~/Library/perl5/lib/perl5 -Mlocal::lib=~/Library/perl5`
echo 'eval `perl -I ~/Library/perl5/lib/perl5 -Mlocal::lib=~/Library/perl5`' >> ~/.bash_profile