$ curl cheat.sh/
# amixer
# Mixer for ALSA soundcard driver.
# More information: <https://manned.org/amixer>.

# Turn up the master volume by 10%:
amixer -D pulse sset Master 10%+

# Turn down the master volume by 10%:
amixer -D pulse sset Master 10%-

$
Follow @igor_chubin cheat.sh tldr