Learning Perl, Fourth Edition

Installing Modules

When you want to install a module you don’t 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,^[339] 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, 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 come with Perl: CPAN.pm.^[340] From the command line, you can start up the CPAN.pm shell, from which you can issue commands.

    $ perl -MCPAN -e shell

Even this can be complicated, so a while ago one of our authors wrote a little script called cpan, which 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

“I don’t have a command line!” you might be saying. If you are using the ActiveState port of Perl (for Windows, Linux, or Solaris), you can use the Perl Package Manager (PPM),^[341] which installs modules ...