Perl is a well-known programming language and one of its major advantages is that it works with the so-called modules - short bits of program code which contain subroutines and execute different tasks. The convenient side of using modules is the fact that you won't need to write custom code or add the entire code for a given process every single time it should be performed. Alternatively, you'll be able to include only a single line in your Perl script which calls a given module, which in turn will perform the needed action. Not only will this give you shorter and optimized scripts, but it will also enable you to make changes a lot quicker and much easier. If you are not a programmer, still you'd like to start using a Perl application which you've discovered online, for instance, it's likely that the app will need certain modules to be already set up on the web hosting server.