Here are some handy command-line invocations for living with Docker.
Clean up all your exited containers:
docker ps -a | awk '/ Exited / {print $1}' | xargs docker rm
Remove untagged, unused image layers:
docker images | awk '/<none>.*<none>/ {print $3}' | xargs docker rmi
Spin a Docker container, but get in there and poke around:
docker run -it --entrypoint /bin/bash <IMAGE>
Run a Docker container, but drop all the privileges and capabilities that
make root special:
docker run --cap-drop=all <IMAGE>