Docker Basics: Essential Commands with Examples for Beginners

If you’re getting started with Docker, knowing the basic commands is the first step to managing containers and images effectively. This guide covers the most common Docker commands, explains what they do, and provides practical examples to help you get up and running quickly.

Managing Docker Images

Docker images are the blueprints for containers. Here’s how to work with them.

1. docker images

Lists all Docker images stored locally.

Example:

docker images

Output:

REPOSITORY   TAG       IMAGE ID       CREATED        SIZE
nginx        latest    abc123def456   2 weeks ago    133MB
ubuntu       20.04     xyz789uvw321   3 weeks ago    72.8MB

2. docker pull

Downloads an image from Docker Hub to your local machine.

Syntax:

docker pull <IMAGE_NAME>:<VERSION>

Example:

docker pull redis:alpine

3. docker image rm

Removes a specific image from your local registry.

Syntax:

docker image rm <IMAGE_ID>

Example:

docker image rm abc123def456

4. docker rmi (alternative)

Same as docker image rm, but shorter syntax.

Example:

docker rmi abc123def456

Managing Docker Containers

Containers are running instances of images.

5. docker ps

Lists only running containers.

Example:

docker ps

6. docker ps -a

Lists all containers, including stopped ones.

Example:

docker ps -a

7. docker run

Creates and starts a new container from an image. If the image isn’t local, Docker pulls it first.

Basic Syntax:

docker run <IMAGE_NAME>:<VERSION>

Common Options:

• --name <NAME> – Assign a custom name to the container.
• -p <HOST_PORT>:<CONTAINER_PORT> – Map a host port to a container port.
• -d – Run the container in detached (background) mode.
• -it – Run interactively with a terminal.

Example:

docker run --name my-web -p 8080:80 -d nginx:latest

This runs an Nginx container named my-web, mapping host port 8080 to container port 80, in the background.

Running and Stopping Containers

8. docker stop

Gracefully stops a running container.

Syntax:

docker stop <CONTAINER_ID_OR_NAME>

Example:

docker stop my-web

9. docker start

Restarts a stopped container.

Example:

docker start my-web

10. docker restart

Restarts a running container.

Example:

docker restart my-web

11. docker pause / docker unpause

Pauses or unpauses a running container without stopping it.

Example:

docker pause my-web
docker unpause my-web

12. docker kill

Forcibly stops a container (SIGKILL).

Example:

docker kill my-web

Inspecting and Interacting with Containers

13. docker logs

Shows the logs of a container.

Example:

docker logs my-web

Follow logs in real-time:

docker logs -f my-web

14. docker exec

Runs a command inside a running container.

Example:

docker exec -it my-web /bin/bash

This opens an interactive bash shell inside the my-web container.

15. docker inspect

Returns detailed information about a container or image in JSON format.

Example:

docker inspect my-web

Cleanup Commands

16. docker container rm

Removes a stopped container.

Example:

docker container rm my-web

Force remove a running container:

docker container rm -f my-web

17. Remove all stopped containers:

docker container prune

18. Remove all unused images:

docker image prune -a

19. Remove all images (forceful):

docker image rm -f $(docker images -aq)

20. Remove all containers (forceful):

docker container rm -f $(docker ps -aq)

Extra Useful Commands

21. docker build

Builds an image from a Dockerfile.

Example:

docker build -t my-custom-image:1.0 .

22. docker tag

Tags an image with a new name or version.

Example:

docker tag my-image:latest my-image:v1

23. docker network ls

Lists all Docker networks.

Example:

docker network ls

24. docker volume ls

Lists all Docker volumes.

Example:

docker volume ls

25. docker-compose up

Starts services defined in a docker-compose.yml file.

Example:

docker-compose up -d

Conclusion

These Docker commands form the foundation of container management. Practice them regularly to build confidence in deploying, managing, and troubleshooting containers. As you advance, explore Docker Compose, Docker Swarm, and Kubernetes for orchestration.

Happy Dockering! 🐳