Just a quickie response (gotta run in a few minutes) but:
check out this node. There are a couple perl modules in the making for nmap as well and I know others will post the links to them shortly, but until they do you may want to spend some more time with joining the nmap-hackers mailing list/forum. Quite a few topics such as this have come through there in the last few weeks.

Also, from this node, here is a code snippet for reading in a file:

open (INPUT, $filename) || die "Can't open $filename: $!";
while (<INPUT>) {
    hack($_);
    slice($_);
    dice($_);
    vacuum_seal($_);
}
close INPUT || die "Wow, we're in for it now: $!";
[download]

Here are a few more nodes to look at on the subject. Another thing to look into might be File::Slurp? And never forget (as I was recently reminded by The Footpad *grin*) - supersearch is your friend!

*G*