Reported by Britton Leo Kerin at http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=359948 Actually the man page doesn't really even say that -f is going to require -d, and the error message that you get when you try -f alone doesn't say that you need to have the -d preceed the -f, though this requirement probably makes sense. So it ends up looking like it just doesn't work unless you happen to try switching the options around.