While I LOVE Perl, I disagree in this case.

If the only thing needing to be checked is permissions, the following would suffice:

find / -exec ls -l {} \; > /tmp/pass1
find / -exec ls -l {} \; > /tmp/pass2
diff /tmp/pass1 /tmp/pass2
[download]

Of course you would tailor the find command as PrimeLord indicated (only get specific files with permissions).

In my experience, this specific task is faster/easier/efficient using Unix commands.

Cheers - L~R