This is helpful if you need to control the volume on a Mac that you have access to via SSH, or need to control it with a bash script.
Basic syntax
sudo osascript -e "set volume (0-10)"
Turn volume off
sudo osascript -e "set volume 0"
Turn volume to 100%
sudo osascript -e "set volume 10"
Turn volume to 51%
sudo osascript -e "set volume 5.1"