Docker

PDF Markdown HTML

The commands you reach for daily with the Docker CLI. docker compose (v2, a subcommand) has replaced the old docker-compose binary — both are shown where they differ.

Images

Command	Action
docker build -t app:1.0 .	build an image from the Dockerfile here
docker images	list local images
docker pull nginx:alpine	download an image
docker tag app:1.0 app:latest	add another tag
docker push registry/app:1.0	upload to a registry
docker rmi app:1.0	remove an image

Containers

Command	Action
docker run nginx	run a container in the foreground
docker ps	list running containers
docker ps -a	list all containers, including stopped
docker stop <id>	graceful stop (SIGTERM)
docker start / restart <id>	start / restart a container
docker rm <id>	remove a stopped container
docker exec -it <id> sh	open a shell inside a running container
docker logs -f <id>	follow a container's logs

Common run flags

Flag	Effect
-d	detached — run in the background
-p 8080:80	map host port 8080 to container port 80
-v ./data:/app/data	bind-mount a host folder
-e KEY=value	set an environment variable
--name web	give the container a stable name
--rm	auto-remove the container when it exits
--network mynet	attach to a user-defined network

A typical one-liner

docker run -d --name web --rm \
  -p 8080:80 -v ./html:/usr/share/nginx/html \
  nginx:alpine

Compose

Command	Action
docker compose up -d	start the stack in the background
docker compose down	stop and remove the stack
docker compose ps	list the stack's containers
docker compose logs -f	follow logs for all services
docker compose build	rebuild service images
docker compose restart <svc>	restart one service

Clean Up

Command	Removes
docker system df	show what Docker is using (safe)
docker container prune	all stopped containers
docker image prune	dangling (untagged) images
docker image prune -a	all images not used by a container
docker volume prune	unused volumes
docker system prune -a	containers, networks, and unused images

prune deletes without asking twice. docker volume prune can wipe database data living in an unused volume, and system prune -a removes every image no running container references. Check docker system df first.