The camel survives!

About installing Perl in hostile environments.

• Motivation
• Bootstrap
  • Requirements
  • Choose your target
  • Get cpanm
  • Install local::lib
  • Try it
  • Get CPAN
• Upgrade Perl
• See also

Motivation

Right now I’m working on a Centos 6 Linux box. I have no cpan client

$ cpan
-bash: cpan: command not found

and a deprecated version of Perl :(

$ perl -v

This is perl, v5.10.1 ...

What is worse is that I will deploy on a host with no Internet access, probably with no root permissions … but there is a hope

The camel survives!

Bootstrap

Requirements

You need to install ExtUtils::MakeMaker.

If you get errors like

Can't locate ExtUtils/MakeMaker.pm in @INC

probabily is not installed. That is a silly choice of some Linux distros, yes I said silly cause ExtUtils::MakeMaker is a core module and it should be provided with any Perl distribution.

Get root permissions and install it, on Centos just launch

$ yum install perl-ExtUtils-MakeMaker

If you can’t do it, go straight and compile your own Perl: see .software.

Choose your target

Create a folder that will be your Perl home. To make it easier, I choose local::lib default

$ export PERL_BASE=~/perl5

Get cpanm

As documented in App::cpanminus related section, get a standalone cpanm executable to bootstrap your Perl.

$ mkdir -p $PERL_BASE/bin
$ cd $PERL_BASE/bin
$ curl -LO http://xrl.us/cpanm
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  262k  100  262k    0     0   279k      0 --:--:-- --:--:-- --:--:--  279k
$ chmod +x cpanm

Install local::lib

Now you can install local::lib locally

$ ./cpanm -l $PERL_BASE local::lib

Load special environment variables. Note that ~/.perl_profile file will be overwritten.

$ cd $PERL_BASE/lib/perl5
$ perl -Mlocal::lib=$PERL_BASE > ~/.perl_profile
$ source ~/.perl_profile

Make it permanent, edit your profile. For example you can launch

$ grep 'source ~/.perl_profile' ~/.bash_profile || echo 'source ~/.perl_profile' >> ~/.bash_profile

which will add source ~/.perl_profile to your .bash_profile only once.

Try it

At this point you have your system Perl with a cpanm that can install locally

Give it a try it, install Perl::Tidy

$ cpanm Perl::Tidy
   Working on Perl::Tidy
Fetching http://www.cpan.org/authors/id/S/SH/SHANCOCK/Perl-Tidy-20140328.tar.gz ... OK
Configuring Perl-Tidy-20140328 ... OK
Building and testing Perl-Tidy-20140328 ... OK
Successfully installed Perl-Tidy-20140328
1 distribution installed
$ which perltidy
~/perl5/bin/perltidy

Get CPAN

Now you can choose, to keep cpanm or get the official CPAN client

$ cpanm CPAN

Then maybe you want A CPAN client that works like a charm.

Upgrade Perl

Use Perlbrew to install, upgrade and manage your Perl installation.

$ export PERLBREW_ROOT=$PERL_BASE/perlbrew
$ echo export PERLBREW_ROOT=$PERLBREW_ROOT >> ~/.perl_profile

Install it

$ cpanm App::perlbrew

Then initialize it and add it to your environment with

$ perlbrew init

perlbrew root (~/perl5/perlbrew) is initialized.

Append the following piece of code to the end of your ~/.bash_profile and start a
new shell, perlbrew should be up and fully functional from there:

    source ~/perl5/perlbrew/etc/bashrc

Simply run `perlbrew` for usage details.

Happy brewing!

$ source ~/perl5/perlbrew/etc/bashrc
$ echo 'source ~/perl5/perlbrew/etc/bashrc' >> ~/.perl_profile

Install patchperl (only once)

$ perlbrew install-patchperl

Now you can install and upgrade Perl easily, for example

$ perlbrew install perl-5.16.0
$ perlbrew switch perl-5.16.0

See also

• A CPAN client that works like a charm