If there is a problem to solve, somebody has probably already solved it and made their solution available on the Comprehensive Perl Archive Network (CPAN), which is a worldwide collection of servers and mirrors containing thousands of modules of reusable Perl code. Indeed, most of Perl 5 is in the modules since Larry designed it as an extensible language.
We’re not going to teach you how to write modules here: you’ll have to get that from Intermediate Perl. In this chapter, we’ll show you how to use modules that already exist. The idea is to get you started with CPAN rather than give you a survey on modules.
Modules come in two types: those that come with Perl that you should have available to you, and those that you can get from CPAN to install yourself. Unless we say otherwise, the modules that we show come with Perl.
Some vendors provide even more modules with their stock versions of Perl. There’s actually a third type: vendor modules, but those are a bonus. Check your operating system to see what else you might have.
To find modules that don’t come with Perl, start at either CPAN Search or MetaCPAN. You can also browse the distribution and have a peek at the files without the bother of installing the modules. You can read the module documentation before you download the entire package. There are many other tools for inspecting a distribution too.
But, before you go looking for a module, you should check if it is already installed. One way ...