On Mon, 13 Dec 2010, Keith Roberts wrote: > I know about audacity, but I want a command line tool that > will work overnight, on a batch of mp3 files, each about > 15MB per hour. You've got a command line tool that does what you need, it just needs rebuilding with mp3 support. I'm with John Doe's suggestion on this one. Install lame-devel from rpmforge, download the src.rpm for sox, rpmbuild --rebuild it, install it, mp3 support is now in. jh