Prerequisites:
# stuff these into a shell startup file (like .zshrc)
alias imdone='afplay /System/Library/Sounds/Blow.aiff'
# if you want to play a sound at random then use the following line
# alias imdone='afplay "$(find /System/Library/Sounds -type f -name "*.aiff" | shuf -n 1)"'
alias iwatch='while true; do rm ./imdone; watch -g ls ./imdone; imdone; done'