Thanks for that Phil. I gave your suggestion a go and it would definitely work except that it is returns quite a few false-positives. However, it gave me the inspiration to try again and I finally found a Perl script that actually works and then spent the afternoon molding it into a Nagios plugin that I just got working a few minutes ago. I'll do up a blog post about it tomorrow with the code for my nagios plugin since it's a hacked version of a GPL script.