Swiss army knife of sound processing

 SoX is a command line utility that can convert various formats of computer
 audio files in to other formats. It can also apply various effects to these
 sound files during the conversion. As an added bonus, SoX can play and record
 audio files on several unix-style platforms.
 .
 SoX is able to handle formats like Ogg Vorbis, MP3, WAV, AIFF, VOC, SND, AU,
 GSM and several more.
 Any format support requires at least libsox-fmt-base. Some formats have their
 own package e.g. mp3 read and write support is provided by libsox-fmt-mp3.
 .
 SoX supports most common sound architectures i.e. Alsa, Libao, OSS and Pulse
 (respectively provided by libsox-fmt-alsa, libsox-fmt-ao, libsox-fmt-oss and
 libsox-fmt-pulse). It also supports LADSPA plugins.