Perl is a widely used programming language and among its main advantages is that it supports the so-called modules - short pieces of code that include subroutines and perform various tasks. The beneficial side of using modules is the fact that you won't need to write custom program code or add the whole code for a specific process every time it has to be performed. Instead, you will be able to include just one line in your Perl script which calls a certain module, that consequently will execute the necessary task. Not only will this provide you with shorter and more optimized scripts, but it'll also enable you to make changes quicker and much easier. In case you aren't a programmer, still you'd like to start using a Perl app which you've found on the Internet, for instance, it is very likely that the application will require some modules to be already installed on your hosting server.