At the moment, the way I am doing it is with the pipe. The reason that I was looking for a more pure-perl implementation or a wrapped c-code implementation was that this is running in a script that sometimes runs MANY times (often simultaneously) (it's a ftp-server postprocessor). The need for the lsof call is that there is some apparent corruption happening on certain files (and they are all rijndael encrypted, hence 1 1 byte corruption is VERY bad!!) and it appears to me that the FTP server is holding open a file during a rename and I am processing the file prior to it flushing the buffer or something.

Tha bug is very frustrating, and also quite difficult to track down. It's a complex system involving PocketPC devices, a linux server running proftpd, plus lots of backend post-processing of the files created by the pocketpc devices...

Again, thanks for your input. If I find that the numerous piped lsof calls are putting to much of a strain on the server, I'll probably port it to a module (and CPAN it). Might be an interesting foray into the world of XS or inline c!