Perl is a popular scripting language that's used to create various web-oriented applications, such as CGI scripts. Among the attributes that differentiate it from alternative languages is the usage of modules - parts of Perl code which execute predefined jobs and they are universally accepted. Basically, instead of writing custom program code to do something or pasting tens and hundreds of lines of code in the script, you will be able to "call" some module which already exists for this particular job and use just several lines of program code. In consequence, your script shall be executed faster since it will be smaller. Employing modules will, in addition make a script simpler to change since you'll have to search through a smaller amount of code. If you wish to use Perl on your site, you need to make sure that the mandatory modules can be found on the server.