Editing CPAN (section)

==Role==
Like many [[programming language]]s, Perl has mechanisms to use external [[library (computing)|libraries]] of code, making one file contain common routines used by several programs. Perl calls these ''modules''. [[Perl module]]s are typically installed in one of several [[directory (computing)|directories]] whose [[path (computing)|paths]] are placed in the Perl [[interpreter (computing)|interpreter]] when it is first [[compiler|compiled]]; on [[Unix-like]] [[operating system]]s, common paths include ''/usr/lib/perl5'', ''/usr/local/lib/perl5'', and several of their subdirectories.

Perl comes with a small set of ''core modules''. Some of these perform bootstrapping tasks, such as ExtUtils::MakeMaker,<ref>{{Cite web|title=ExtUtils::MakeMaker - Create a module Makefile - Perldoc Browser|url=https://perldoc.perl.org/ExtUtils::MakeMaker|access-date=2020-11-18|website=perldoc.perl.org}}</ref> which is used to create [[Makefile]]s for building and installing other extension modules; others, like List::Util,<ref>{{Cite web|title=List::Util - A selection of general-utility list subroutines - Perldoc Browser|url=https://perldoc.perl.org/List::Util|access-date=2020-11-18|website=perldoc.perl.org}}</ref> are merely commonly used.

CPAN's main purpose is to help programmers locate modules and programs not included in the Perl standard distribution. Its structure is decentralized. Authors maintain and improve their own modules. Forking, and creating competing modules for the same task or purpose, is common. There is a third-party bug tracking system that is automatically set up for any uploaded distribution, but authors may opt to use a different bug tracking system such as [[GitHub]]. Similarly, though GitHub is a popular location to store the source for distributions, it may be stored anywhere the author prefers, or may not be publicly accessible at all. Maintainers may grant permissions to others to maintain or take over their modules, and permissions may be granted by admins for those wishing to take over abandoned modules. Previous versions of updated distributions are retained on CPAN until deleted by the uploader, and a secondary mirror network called BackPAN retains distributions even if they are deleted from CPAN.<ref>{{cite web |title=BackPAN |url=http://backpan.cpantesters.org/ |access-date=20 December 2019}}</ref> Also, the complete history of the CPAN and all its modules is available as the GitPAN project,<ref name="gitpan-readme">{{cite web|url=https://github.com/evalEmpire/gitpan/blob/master/README.md|date=2 December 2015|access-date=16 November 2016|title=What is Gitpan?|website=[[GitHub]]}}</ref> allowing to easily see the complete history for all the modules and for easy maintenance of forks. CPAN is also used to distribute new versions of Perl, as well as related projects, such as [[Parrot virtual machine|Parrot]] and [[Raku (programming language)|Raku]].