I found this oreilly chapter but it is just opening the pipe ... but hopefully it will be useful for reference if you have to end up going that route..

Update: Ah, crap. i didn't realize where that link was coming from (it was on the first page of google(perl lsof) results). Anyways, the hyperlink is removed now, and apologies, and thanks to sth and caron for noticing. For those w/hard (legal) copies of the book, it was chapter 4.4.2 of "Perl for System Administration".