sox

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

• Merge two audio files into one:
  sox -m {{input_audiofile1}} {{input_audiofile2}} {{output_audiofile}}
• Trim an audio file to the specified times:
  sox {{input_audiofile}} {{output_audiofile}} trim {{start}} {{end}}
• Normalize an audio file (adjust volume to the maximum peak level, without clipping):
  sox --norm {{input_audiofile}} {{output_audiofile}}
• Reverse and save an audio file:
  sox {{input_audiofile}} {{output_audiofile}} reverse
• Print statistical data of an audio file:
  sox {{input_audiofile}} -n stat
• Increase the volume of an audio file by 2x:
  sox -v 2.0 {{input_audiofile}} {{output_audiofile}}