Perl is a preferred scripting language that's that is used to build various web-oriented applications, which includes CGI scripts. One of the features which differentiate it from many other languages is the use of modules - parts of Perl program code that do predefined jobs and they are commonly accepted. In simple terms, as an alternative to creating custom code to do something or pasting tens and hundreds of lines of code in the script, you are able to "call" some module which already exists for this specific process and use only a couple of lines of code. Therefore, your script shall be executed a lot quicker since it is much smaller. Using modules will, in addition make a script easier to edit as you will need to browse through much less program code. In case you'd like to use Perl on your website, you need to make sure that the mandatory modules can be found on your server.