If you use Docker long enough, you eventually hit the same wall:

• Containers are running… but nothing works

• Logs are empty or useless

• You forget the exact command to “just get inside the thing”

• Disk space mysteriously vanishes

This Docker cheat sheet isn’t a full reference manual.
It’s the 90% of Docker commands you’ll actually use, written in plain English, so you can move fast when something breaks.

Bookmark it. You’ll be back.

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Docker Mental Model (30-Second Primer)

Before commands, anchor these concepts:

• Image → A blueprint (read-only)

• Container → A running (or stopped) instance of an image

• Volume → Persistent data outside container lifecycle

• Network → How containers talk to each other

• Dockerfile → Instructions to build an image

• Docker Compose → Runs multi-container apps

If this mental model clicks, Docker becomes predictable instead of frustrating.

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Container Lifecycle Commands

docker run

Create and start a new container.

Most-used flags:

• -d → run in background

• -p 8080:80 → map ports

• --name myapp → name container

• -v host:container → mount volume

• --env KEY=value → environment variable

Example:

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docker start

Start an existing container.

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docker stop

Gracefully stop a container.

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docker restart

Quick reset (stop + start).

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docker rm

Delete a container (must be stopped).

Force remove:

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Inspecting & Debugging Containers

docker ps

List running containers.

Include stopped containers:

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docker logs

View container output.

Follow logs:

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docker exec

Run a command inside a running container.

If bash doesn’t exist (Alpine images):

This is your “open the sealed box” command.

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docker inspect

View detailed container configuration.

Common uses:

• Find container IP

• Check mounted volumes

• Confirm environment variables

• Debug port bindings

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Image Commands

docker images

List local images.

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docker pull

Download an image.

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docker build

Build an image from a Dockerfile.

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docker rmi

Remove an image.

Force:

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Volumes & Persistent Data

docker volume ls

List volumes.

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docker volume inspect

See where data lives on disk.

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docker volume rm

Delete a volume.

⚠️ This deletes data permanently.

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Networking Commands

docker network ls

List networks.

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docker network inspect

See connected containers.

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docker network create

Create a custom network.

Custom networks = cleaner container-to-container communication.

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Docker Cleanup Commands

docker system df

Check disk usage.

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docker system prune

Remove unused containers, images, and networks.

Aggressive cleanup:

If Docker is eating your disk space, this is usually the fix.

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Docker Compose Cheat Sheet

docker compose up

Start all services.

Detached:

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docker compose down

Stop and remove everything.

Remove volumes too:

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docker compose ps

List running services.

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docker compose logs

View service logs.

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docker compose exec

Run a command inside a service.

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Docker Debugging Shortcuts (Memorize These)

• Container won’t start? → docker logs

• Need shell access? → docker exec -it

• Port not working? → docker inspect

• Disk full? → docker system prune

• Data missing? → check volumes

• Multiple containers? → Docker Compose

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Final Thought

Docker isn’t hard.

It’s just unforgiving when you don’t know which command unlocks which door.

This cheat sheet covers the commands that matter—the ones you’ll actually use under pressure.