Docker is a popular containerization tool that allows you to package and run applications in isolated environments. Here are some basic Docker commands that will come in handy if you work with Docker on a daily basis, are looking for a refresher, or are preparing for an interview.
1. Docker Installation Verification
Verify if Docker is installed and check its version.
docker --version
2. Docker Help
Display a list of Docker commands or options available.
docker --help
3. Pull an Image
Pull a Docker image from a repository like Docker Hub.
docker pull <image_name>:<tag>
Example:
docker pull ubuntu:latest
4. List Docker Images
Show all Docker images stored locally.
docker images
5. Run a Container
Run a container from a Docker image.
docker run <image_name>
Example:
docker run -it ubuntu
6. List Running Containers
List all currently running containers.
docker ps
Add the -a option to show all containers, including stopped ones.
docker ps -a
7. Stop a Running Container
Stop a running container using its ID or name.
docker stop <container_id>
Example:
docker stop 1a2b3c4d5e6f
8. Remove a Container
Remove a stopped container.
docker rm <container_id>
Example:
docker rm 1a2b3c4d5e6f
9. Remove an Image
Remove a Docker image from your local system.
docker rmi <image_name>
Example:
docker rmi ubuntu:latest
10. View Container Logs
View the logs generated by a specific container.
docker logs <container_id>
Example:
docker logs 1a2b3c4d5e6f
Add the -f option to follow the logs in real-time:
docker logs -f 1a2b3c4d5e6f
11. View Application Logs Inside a Container
To view logs of an application running inside a container, first access the container and then view the relevant log files.
docker exec -it <container_id> <command>
Example:
docker exec -it 1a2b3c4d5e6f bash
Once inside the container, navigate to the directory where the logs are stored (e.g., /var/log), and use a command like cat, tail, or less to view the logs:
tail -f /var/log/app.log
12. Execute Commands in a Running Container
Execute a command inside a running container.
docker exec -it <container_id> <command>
Example:
docker exec -it 1a2b3c4d5e6f bash
13. Build an Image from a Dockerfile
Build a Docker image from a Dockerfile in the current directory.
docker build -t <image_name> .
Example:
docker build -t myapp:1.0 .
14. Tag an Image
Tag an image with a name before pushing it to a repository.
docker tag <image_id> <repository_name>:<tag>
Example:
docker tag 123abc456def myrepo/myapp:1.0
15. Push an Image to a Repository
Push a tagged image to a Docker registry.
docker push <repository_name>:<tag>
Example:
docker push myrepo/myapp:1.0
16. Remove All Stopped Containers
Remove all stopped containers at once.
docker container prune
17. Remove All Unused Images
Remove all dangling (unused) images.
docker image prune
18. Inspect a Container
Get detailed information about a container in JSON format.
docker inspect <container_id>
Example:
docker inspect 1a2b3c4d5e6f
19. Docker Compose Commands
- Start services defined in a
docker-compose.ymlfile:docker-compose up - Stop services:
docker-compose down
20. Export and Import a Container
- Export a container to a tar file:
docker export <container_id> > <container_name>.tarExample:
docker export 1a2b3c4d5e6f > mycontainer.tar - Import a container from a tar file:
docker import <container_name>.tarExample:
docker import mycontainer.tar
21. Docker System Information
Display system-wide information about Docker, including the number of containers, images, and resources.
docker info
The above commands provide a solid foundation for working with Docker, from managing images and containers to more advanced operations like building images and orchestrating with Docker Compose.
