Learning Perl, 5th Edition

Installing Modules

When you want to install a module that you don’t already have, sometimes you can simply download the distribution, unpack it, and run a series of commands from the shell. Check for a README or INSTALL file that gives you more information. If the module uses MakeMaker,^[†] the sequence will be something like this:

$ perl Makefile.PL
$ make install

If you can’t install modules in the system-wide directories, you can specify another directory with a PREFIX argument to Makefile.PL:

$ perl Makefile.PL PREFIX=/Users/fred/lib

Some Perl module authors use another module, Module::Build, to build and install their creations. That sequence will be something like this:

$ perl Build.PL
$ ./Build install

Some modules depend on other modules though, and they won’t work unless you install yet more modules. Instead of doing all that work ourselves, we can use one of the modules that comes with Perl, CPAN.pm.^[‡] From the command line, you can start up the CPAN.pm, from which you can issue commands:

$ perl -MCPAN -e shell

Even this can be a little complicated, so a while ago one of our authors wrote a little script called “cpan,” which also comes with Perl and is usually installed with perl and its tools. Just call the script with a list of the modules you want to install:

$ cpan Module::CoreList LWP CGI::Prototype

You might be saying, “But I don’t have a command line!” If you are using the ActiveState port of Perl (for Windows, Linux, or Solaris), you can use the Perl Package Manager (PPM), ...