Docker Cheat Sheet

Free Docker cheat sheet: the everyday docker and docker compose commands, Dockerfile instructions and image/container basics at a glance.

Images

Concept	Syntax	Example
Pull an image Downloads an image from a registry like Docker Hub.	`docker pull image:tag`	`docker pull nginx:latest`
Build an image -t tags the image; . is the build context (the Dockerfile dir).	`docker build -t name .`	`docker build -t myapp:1.0 .`
List images Shows local images with their sizes and tags.	`docker images`	`docker images`
Tag an image Add a new name/tag, e.g. before pushing to a registry.	`docker tag src target`	`docker tag myapp:1.0 user/myapp:latest`
Push an image Uploads to a registry; log in first with docker login.	`docker push name:tag`	`docker push user/myapp:latest`

Containers

Concept	Syntax	Example
Run a container -d detaches (background); -p maps host:container ports.	`docker run image`	`docker run -d -p 8080:80 nginx`
Run interactively -it gives an interactive terminal inside the container.	`docker run -it image sh`	`docker run -it ubuntu bash`
List containers ps shows running; -a includes stopped containers.	`docker ps / docker ps -a`	`docker ps -a`
Stop / start Reference containers by name or ID.	`docker stop\|start id`	`docker stop my_container`
Exec into a container Run a command inside a running container.	`docker exec -it id sh`	`docker exec -it web bash`
View logs -f follows (streams) the log output.	`docker logs id`	`docker logs -f web`

Dockerfile

Concept	Syntax	Example
Base image Every Dockerfile starts from a base image.	`FROM image:tag`	`FROM node:20-alpine`
Set working dir Sets the directory for following commands.	`WORKDIR /path`	`WORKDIR /app`
Copy files in ADD also handles URLs and tar extraction.	`COPY src dest`	`COPY . /app`
Run build command Executes during build, creating a new image layer.	`RUN command`	`RUN npm install`
Expose & default command CMD is the default process when the container starts.	`EXPOSE / CMD`	`EXPOSE 3000 CMD ["node", "server.js"]`
Environment variable Sets an env var available to the running container.	`ENV KEY=value`	`ENV NODE_ENV=production`

docker compose

Concept	Syntax	Example
Define services Each service is a container in a multi-container app.	`services: in compose.yaml`	`services: web: image: nginx`
Start everything -d runs in the background; builds images if needed.	`docker compose up`	`docker compose up -d`
Stop everything Stops and removes containers, networks created by up.	`docker compose down`	`docker compose down`
Build & rebuild --build forces a rebuild of service images.	`docker compose build`	`docker compose up --build`
View service logs Aggregates logs from one or all services.	`docker compose logs`	`docker compose logs -f web`

Volumes & Networks

Concept	Syntax	Example
Bind mount Maps a host directory into the container for live files.	`-v host:container`	`docker run -v $(pwd):/app node`
Named volume Docker-managed storage that persists across containers.	`-v name:/path`	`docker run -v db_data:/var/lib/mysql mysql`
List volumes docker volume create name makes one explicitly.	`docker volume ls`	`docker volume ls`
Create a network Lets containers talk to each other by name.	`docker network create name`	`docker network create app_net`
Connect to a network Attach a container to an existing network.	`--network name`	`docker run --network app_net nginx`

Cleanup

Concept	Syntax	Example
Remove a container Container must be stopped first (or use -f).	`docker rm id`	`docker rm my_container`
Remove an image Fails if a container still uses it.	`docker rmi image`	`docker rmi myapp:1.0`
Prune unused Reclaims space; -a also removes unused images.	`docker system prune`	`docker system prune -a`
Remove all stopped Deletes every stopped container at once.	`docker container prune`	`docker container prune`
Auto-remove on exit Cleans up the container automatically when it stops.	`docker run --rm`	`docker run --rm alpine echo hi`