Automute will automatically mute the volume. The first argument takes the seconds. The second argument is whether to put the PC in sleep mode.
write follow command to your .bash_profile or .zshrc
alias automute='bash [path to clone dir]/automute.sh'
alias automute='bash ~/osx-automute-tool/automute.sh'
automute <seconds> [-s]
automute 300
automute 3600 -s