Perl is a well-known programming language and one of its main advantages is the fact that it supports the so-called modules - short bits of program code that include subroutines and do multiple tasks. The practical side of employing modules is that you do not need to write custom code or add the entire code for a certain task every time it needs to be performed. Instead, you will be able to add only a single line in your Perl script which calls a certain module, which in turn will perform the necessary task. Not only will this give you shorter and more optimized scripts, but it will also help you make adjustments quicker and much easier. If you aren't a programmer, yet you would like to employ a Perl app which you've discovered online, for instance, it is likely that the application will require certain modules to be already installed on your hosting server.