Old school way
Kill all running containers
docker kill $(docker ps -q)
Delete all stopped containers (including data-only containers)
docker rm $(docker ps -a -q)
Delete all ‘untagged/dangling’ () images
docker rmi $(docker images -q -f dangling=true)
Delete ALL images
docker rmi $(docker images -q)
Docker command
Since docker 1.25
docker system prune