Cacher is the code snippet organizer for pro developers

awk -F"[][]" '/dB/ { print $2 }' <(amixer sget Master)

ou can use amixer. It's in the alsa-utils package on ubuntu/debian.

Run it without parameters to get an overview about your devices.

amixer

Then use the set command to set the volumn. For example to set the master channel to 50%:

amixer set Master 50