PyMP3Cut is a Python command line tool designed to cut huge (> 100MB) MP3 files at high speed without requiring the extra disk space and processing time usually needed by visual audio editing tools, which convert the MP3 format to more easily manageable formats like WAV before doing anything. It reads and cuts simultaneously according to the autodetected MP3 frame rate and a timeline passed as a command line argument. It doesn't currently deal with Variable Bit Rate (VBR) MP3 files, though.
GNUsound is a sound editor for GNU/Linux. It supports multiple tracks, multiple outputs, and 8, 16, or 24/32-bit samples. It can read and write many audio formats through a number of supported file format libraries (such as AudioFile, libsndfile, and libmp3lame), and it can extract audio from a variety of video files through FFmpeg. It supports OSS, ALSA, or JACK for playback/capture, as well as a large number of high-quality audio effects through the LADSPA plugin architecture.