mp3tools is a set of utilities (mp3id3, mp3info, mp3index, and mp3gui) for managing collections of MPEG audio files. It can get information such as bitrate and play length about a file, view and alter ID3 tags, and generate completely customized listings. All of these functions can be done either from the command line or a GUI.
mpegrec (and wavrec, which is bundled with this program) provide direct-to-disk recording of wav and mp3 files from your sound card. 'lame' is required for mpegrec to encode audio on-the-fly to mp3. mpegrec is a simple, multithreaded (and multi-buffering) C application. It has been tested on a dual PII-450 running Linux Mandrake 7.0 with a Soundblaster PCI128 and works well capturing audio at 44.1kHz stereo directly to a 192kb mp3 file. The commandline interface is simple and allows recording for a specified number of seconds, or until Control-C is hit.
mpg321 is a Free clone of mpg123, a command-line MP3 player. It is designed to be a drop-in replacement for mpg123, and therefore its interface has been designed around that of mpg123, without using any of its code. mpg321 has been designed for use with frontends such as gqmpeg, although it is just as useful on the command-line. Unlike mpg123, it supports ESD and ALSA output without recompiling, and it does all MP3 decoding with only fixed-point math by using the mad MPEG audio decoder library.
mpgfe is an ncurses front-end to mpg123 with mouse support via GPM, advanced playlist editing features (load/save/add playlists in m3u format, order/shuffle a playlist, move/add/delete playlist entries), and resizing support. An interesting feature is the ability to display the lyrics of the song that is playing (provided that you added the name of the lyrics file after the song file. Song information is displayed while playing, in a customizable format. Volume control is available (both channels at a time) and also movement. You can display the length of every song and total playing time. The super user may run the player with real-time priority (playing will not be interrupted by disk access).