Perl in a Nutshell

Getting and Installing Modules

As you’ll see when you look at the lists of modules and their authors on CPAN, many users have made their modules freely available. If you find an interesting problem and are thinking of writing a module to solve it, check the modules directory on CPAN first to see if there is a module there that you can use. The chances are good that there is either a module already that does what you need, or perhaps one that you can extend, rather than starting from scratch.^[3]

Before you download a module, you might also check your system to see if it’s already installed. The following command searches the libraries in the @INC array and prints the names of all modules it finds:

find `perl -e 'print "@INC"'` -name '*.pm' -print

Locating modules

If you start from the modules directory on CPAN, you’ll see that the modules are categorized into three subdirectories:

by-authors       Modules by author's registered CPAN name
by-category      Modules by subject matter (see below)
by-module        Modules by namespace (i.e., MIME)

If you know what module you want, you can go directly to it by clicking on the by-module entry. If you are looking for a module in a particular category, you can find it through the by-category subdirectory. If you know the author, click on by-author. However, if you aren’t familiar with the categories and you want to find out if there is a module that performs a certain task, you might want to get the file 00modlist.long.html, also in the modules directory. That ...