Perl Module Tips

This a bit of pre-emptive blogging, for the next time I forget. Those of you with stronger Perl-fu than I already know these things.

How to check if a module is installed:

No output indicates success : perl -MMODULENAME -e1

For example: perl -MHTML::Embperl -e1

How to check the version number of an installed module:

Assumes the module uses $VERSION, but then, most CPAN modules do) : perl -MMODULENAME -e’print “$MODULENAME::VERSION\n”;’

For example: perl -MHTML::Embperl -e’print “$HTML::Embperl::VERSION\n”;’

How to determine where a module is installed:

Lists every dir used by the module, including man pages, etc. Should be entered on one line. :

perl -MExtUtils::Installed 
  -e'$,="\n";print ExtUtils::Installed->new()->directories("MODULENAME")," "'

For example:

perl -MExtUtils::Installed
  -e'$,="\n";print ExtUtils::Installed->new()->directories("HTML::Embperl")," "'

This technique relies on ExtUtils::Installed, which is part of the standard Perl distro these days.

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Posted September 14th, 2004 at 6:49 pm 2 Comments »

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2 Responses to “Perl Module Tips”

  1. pjm Says: June 13th, 2005 at 3:34 pm

    http://www.flashesofpanic.com

    Oh, that first one saved me some time this afternoon. (Time I’m using to comment here, but oh well…)

  2. Joe Says: March 25th, 2011 at 1:19 pm

    Jason, thank you very much for the tip “How to check the version number of an installed module”! I needed it the check that I met all the CPAN module requirements before upgrading my SpamAssassin server.