Run and inspect containers from the command line.

Docker

See what is actually running

docker ps --format '{{.Names}}\t{{.Status}}\t{{.Ports}}'

Shell into a stopped container to find out why

docker start -ai <name> sh

What is using that port

docker ps --filter publish=8080

Free disk taken by build cache

docker system df
docker builder prune -f

Volumes survive docker system prune unless you add --volumes. Check docker system df before pruning.

Scope: Docker