Remove dangling images:

docker images -q --filter dangling=true | xargs docker rmi

Remove stopped containers:

docker ps -q --filter status=exited | xargs docker rm -vf

Remove dangling volumes:

docker volume ls -q --filter dangling=true | xargs docker volume rm

Host hack without running a container: --add-host hostname:IP

Trash everything

docker ps -aq | xargs docker rm -vf
docker images -aq | xargs docker rmi -f

Flatten image:

docker export <image> | docker import - <new_name>

Docker Container lifecycle: https://docs.docker.com/reference/api/docker_remote_api/