You need to use instmodsh (interactive inventory for installed Perl modules) command to find out what modules already installed on my system. instmodsh command provides an interactive shell type interface to query details of locally installed Perl modules. It is a little interface to ExtUtils::Installed to examine locally* installed modules, validate your packlists and even create a tarball from an installed module.
Task: List installed perl module
To display the list enter the following command:
Available commands are: l - List all installed modules m - Select a module q - Quit the program cmd?
At cmd? prompt type l to list all installed modules:
Installed modules are: Archive::Tar CPAN Class::Spiffy Compress::Zlib Cwd Digest::SHA IO::Zlib MIME::Lite Module::Build Module::Signature Net::Telnet PAR::Dist Perl Spiffy Term::ReadLine Test::Base Test::Simple Text::Glob Weather::Com XML::Simple YAML cmd?
This command itself is a perl script that use ExtUtils::Installed module. Try following command to see its source code:
$ vi $(which instmodsh)