$ amixer sset Master toggle Simple mixer control 'Master',0 Capabilities: pvolume pswitch pswitch-joined Playback channels: Front Left - Front Right Limits: Playback 0 - 31 Mono: Front Left: Playback 28 [90%] [-4.50dB] [off] Front Right: Playback 28 [90%] [-4.50dB] [off]
$ amixer sset Master toggle
Simple mixer control 'Master',0
Capabilities: pvolume pswitch pswitch-joined
Playback channels: Front Left - Front Right
Limits: Playback 0 - 31
Mono:
Front Left: Playback 28 [90%] [-4.50dB] [off]
Front Right: Playback 28 [90%] [-4.50dB] [off]