It uses strace, a Linux-specific file change notification hook. It's not available on BSD or (IIRC) OS X, though ktrace is, so it could conceivably be ported. (

It uses strace, a Linux-specific file change notification hook. It's not available on BSD or (IIRC) OS X, though ktrace is, so it could conceivably be ported. (The page says something vague about cygwin having a comparable hook to strace. I haven't developed for cygwin, though.) It looks like it checks for files modified specifically by its subprocesses.