ImageMagick is a handy, powerful command-line tool that can crop, scale, rotate, change format, apply basic (and some not-so-basic) effects to pretty much all sorts of images. Does something like it exist for audio?
Barring some sort of omni-tool like that, I need something at the moment to join together a bunch of tracks from a concert and (separately) transcode dozens of files from FLAC to something more supported.