Generating a notification sound in command-line

You want to play a notification sound in a Linux shell script, but don’t want to download any sound files (e.g. MP3, WAV, MIDI). Here is a script that generates the sound on-the-fly:

First install SoX, the Swiss Army knife of sound processing programs.

sudo apt-get install sox

Then:

play -n synth 0.3 pluck A3 vol -20dB repeat 2

• play: the player command from SoX.
• -n: Play a “null file”.
• synth 0.3 pluck A3: Play the A3 (220.00 Hz) sound for 0.3 seconds, with a waveform that simulates a guitar string pluck.
• vol -20dB: The default is too loud, reduce the volume by -20dB.
• repeat 2: Repeat twice (i.e., total 3 times).