Try to run perl -MModule::Name -e 1. If the module is installed, it will print nothing; otherwise it will print an error:

[sgifford@sghome ucspi-tcp-0.88]$ perl -MFile::Copy -e 1

[sgifford@sghome ucspi-tcp-0.88]$ perl -MUninstalled::Module -e 1
Can't locate Uninstalled/Module.pm in @INC (@INC contains: /usr/lib/pe
+rl5/5.6.1/i386-linux /usr/lib/perl5/5.6.1 /usr/lib/perl5/site_perl/5.
+6.1/i386-linux /usr/lib/perl5/site_perl/5.6.1 /usr/lib/perl5/site_per
+l/5.6.0/i386-linux /usr/lib/perl5/site_perl/5.6.0 /usr/lib/perl5/site
+_perl .).
BEGIN failed--compilation aborted.
[download]