Docker cheat sheet

The commands you learned, in one place.

Your laptop (D0 basics)

docker versionIs Docker here and awake?
docker infoCounts of containers and images, and more.
docker run -d --name web -p 8080:80 nginx:1.30-alpineRun nginx in the background. Open hatch 8080.
docker run hello-worldYour first container: it prints a hello.
docker run --rm alpine:3.22 echo hiRun once, then clean the box away.
docker run -it alpine:3.22 shGet a shell inside. Type exit to leave.
docker run -d -e POSTGRES_PASSWORD=secret postgres:18-alpineGive the app a setting with -e.
docker run -d -v pgdata:/var/lib/postgresql postgres:18-alpineKeep data in a locker (volume).
docker ps -aShow all containers, stopped ones too.
docker ps -qOnly the ids.
docker ps --filter status=exitedOnly stopped containers.
docker stop webStop web. It still exists.
docker start webStart it again.
docker restart webStop and start in one go.
docker kill webStop at once, no clean-up (exit 137).
docker pause webFreeze it; docker unpause web wakes it.
docker port web80/tcp -> 0.0.0.0:8080 means: use localhost:8080.

docker logs webRead web's messages.
docker logs -f webKeep watching new lines. Ctrl+C stops.
docker logs --tail 5 webOnly the last 5 lines.
docker exec -it web shStep inside web. exit brings you back.
docker exec web ls /usr/share/nginx/htmlRun one command and come back.
docker inspect -f '{{.State.Status}}' webJust the state of web.
docker top webnginx's master and workers.
docker stats --no-streamMemory and CPU of each container, once.
docker infoLook for Default Runtime: runc and Cgroup Version.
docker diff boxEvery change in box, compared with its image.
docker cp index.html web:/usr/share/nginx/html/Put a page into web.Risk: Careful
docker cp web:/etc/nginx/conf.d/default.conf .Copy a file out.Risk: Careful

docker volume create pgdataMake a locker called pgdata.Risk: Careful
docker volume lsList your lockers.Risk: Careful
docker volume rm pgdataDelete a locker and its data. Careful!Risk: Careful
docker volume inspect pgdataWhere the locker lives, and when it was made.Risk: Careful
docker run --rm -v pgdata:/from -v "$PWD":/to alpine:3.22 tar czf /to/backup.tar.gz -C /from .Back up a locker into one file here.Risk: Careful
docker network create shopnetA new line. Start containers with --network shopnet.
docker network connect shopnet webPlug a running container in.
docker network lsList the lines: bridge, host, none and yours.
docker network inspect shopnetSee who is plugged into shopnet.

docker rm webRemove web. Volumes stay.Risk: Can lose work
docker rm -f webStop and remove a running one. Careful!Risk: Can lose work
docker rmi diary:1.0Remove diary:1.0.Risk: Careful
docker system dfRECLAIMABLE is what a clean-up could free.
docker system pruneIt asks first. y deletes, N keeps.Risk: Can lose work
docker container pruneOnly stopped containers.Risk: Can lose work
docker image prune -aEvery image no container uses.Risk: Can lose work
docker volume pruneUnused unnamed volumes. With -a: all unused volumes!Risk: Can lose work
docker builder pruneOld build cache.Risk: Can lose work