Stopping All Containers
$ docker stop $(docker ps -a -q)
Removing All Containers
$ docker rm $(docker ps -a -q)
This makes it 10x easier for when I want to easily start everything over from scratch If you can remove all images/containers then:
docker rm $(docker ps -a -q)
docker rmi $(docker images -q)
docker volume rm $(docker volume ls |awk '{print $2}')
rm -rf ~/Library/Containers/com.docker.docker/Data/*
Remove all untagged images
docker rmi $(docker images | grep "^<none>" | awk "{print $3}")