The focus of this is knowing the minimum possible to be able to do one liners, specially in text processing.
For larger programs, use Python instead, because Perl is too insane and is dead.
Perl is part of the LSB, and should come with any Linux distro (like Python).
The following contains lots of man pages and HTML docs:
man perlrun
man perldoc
man perlcheat
In Ubuntu install docs with:
sudo aptitude install -y perl-doc
Name of the major package repository for Perl modules, and of the command line tool used to install them.
Install the original markdown:
cpan Text::Markdown
TODO does not install it as an executable. TODO how to do it?