Linux: Change Volume by Command

Here's shell command to change sound volume.

# increase sound level
amixer set Master 8%+

# decrease sound level
amixer set Master 8%-

# set to specific sound level
amixer set Master 50%

you can setup a key such as Super+↑ and Super+↓ to adjust sound level. See Linux: Keyboard Software Guide .

mute and unmute

# mute
amixer set Master mute

# need to run all the following to unmute
amixer set Master unmute
amixer set Headphone unmute
amixer set PCM unmute
amixer set Front unmute
amixer set Surround unmute
amixer set Center unmute
amixer set LFE unmute
amixer set Side unmute

2014-09-10 thanks to [Adam Arvidsson https://plus.google.com/+AdamArvidsson/posts]

Interactively Adjust Sound Level in Terminal

Here's how to change sound interactively in terminal.

Start alsamixer in terminal.

# show a text gui mixer control panel
alsamixer

Then, you can use up/down arrow keys to adjust volume.

Mouse scroll-wheel also works, if your terminal supports it.