http://www.perlmonks.org?node_id=338107
Description: This little snippet allows you to verify that all the modules that the .packlist files say are installed on your system are indeed installed properly. If you need to remove some modules so that they can properly be re-installed, the example in ExtUtils::Packlist shows how to do that
#!/usr/bin/perl
use strict;
use warnings;
use ExtUtils::Installed;

my $packlist = ExtUtils::Installed->new;

for my $module ( $packlist->modules ) {
    my @missing = $packlist->validate( $module );
    if ( @missing ) {
        print "$module is b0rked - missing file(s)\n";
        print "\t$_\n" for @missing;
    }
}