docker run -d --name web -p 8080:80 nginxDetached, named, host port 8080 → container 80.
Docker cheat sheet
The docker CLI commands you actually need, plus Dockerfile instructions. For multi-container setups see the Docker Compose cheat sheet.
20 entries
Run containers
docker run --rm -it python:3.12 bashInteractive throwaway container.
docker run -e NODE_ENV=production --env-file .env appEnvironment variables.
docker run -v $(pwd):/app -w /app node:22 npm testBind-mount the current folder.
Manage containers
docker ps
docker ps -aRunning / all containers.
docker logs -f webFollow logs.
docker exec -it web shShell inside a running container.
docker stop web
docker start web
docker rm webStop, start, remove.
docker inspect web
docker statsDetails; live resource usage.
Images
docker build -t myapp:1.0 .Build from the Dockerfile in this folder.
docker images
docker rmi myapp:1.0List / remove images.
docker tag myapp:1.0 ghcr.io/me/myapp:1.0
docker push ghcr.io/me/myapp:1.0Tag and push to a registry.
docker pull postgres:16Download an image.
Volumes & networks
docker volume create pgdata
docker run -v pgdata:/var/lib/postgresql/data postgres:16Named volume survives container removal.
docker network create appnet
docker run --network appnet --name db postgres:16Containers on one network reach each other by name.
Cleanup
docker system dfDisk used by images, containers, volumes.
docker system pruneRemove stopped containers, unused networks, dangling images.
docker image prune -aRemove all unused images.
Dockerfile
FROM python:3.12-slim
WORKDIR /app
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
COPY . .
USER 1000
EXPOSE 8000
CMD ["gunicorn", "-b", "0.0.0.0:8000", "app:app"]Copy dependency files first so the install layer is cached.
FROM node:22 AS build
WORKDIR /app
COPY . .
RUN npm ci && npm run build
FROM nginx:alpine
COPY --from=build /app/dist /usr/share/nginx/htmlMulti-stage build keeps the final image small.
Frequently asked questions
What is the difference between an image and a container?
An image is a read-only template (layers of files plus metadata). A container is a running (or stopped) instance of an image with its own writable layer.
CMD vs ENTRYPOINT?
ENTRYPOINT sets the executable that always runs; CMD supplies default arguments that docker run can override. Use exec form (JSON array) for both so signals reach your process.
How do I free disk space used by Docker?
Check with docker system df, then run docker system prune. Add -a to also remove unused images and --volumes to remove unused volumes (careful: that deletes data).