Shutdown Docker for mac if no containers are running

docker-shutdown.sh

#!/bin/bash

TIMEOUT=$1
LAST_USED_FILE=~/.docker_last_usage

docker ps -q > /dev/null 2> /dev/null
result=$?

if [[ $result -eq 0 && -z $(docker ps -q) && $(cat $LAST_USED_FILE 2> /dev/null) && $(expr $(date +%s) - $(cat $LAST_USED_FILE 2> /dev/null)) -gt $TIMEOUT ]]; then 
	osascript -e 'quit app "Docker"'
elif [[ $result -eq 0 && -n $(docker ps -q) ]]; then
	date +%s > "$LAST_USED_FILE"
elif [[ $result -eq 0 && ! -f $LAST_USED_FILE ]]; then
	date +%s > "$LAST_USED_FILE"
elif [[ $result -ne 0 ]]; then
        rm -f $LAST_USED_FILE
fi