sox

Sound eXchange: play, record and convert audio files. Audio formats are identified by the extension. More information: http://sox.sourceforge.net.

sox -m path/to/input_audio1 path/to/input_audio2 path/to/output_audio

sox path/to/input_audio path/to/output_audio trim start duration

sox --norm path/to/input_audio path/to/output_audio

sox path/to/input_audio path/to/output_audio reverse

sox path/to/input_audio -n stat

sox -v 2.0 path/to/input_audio path/to/output_audio