Docker Cheatsheet

Updated Mar 11, 2022 ·

Docker commands

This section provides commands to create, manage, and interact with Docker containers.

Creating and Starting Containers

Create a container (but don't start it yet):
```
docker create <image-id>
```
Start a container:
```
docker start <container-id>
```
Run a container from an image:
```
docker run <image-id>
```

For example, to run an NGINX container, Docker checks the host for the image. If not found, it pulls the image from DockerHub:

sudo docker run nginx

Subsequent executions will reuse the same image. To see valid options for the run command:

docker run --help

Listing Containers

List running containers:
```
docker ps
```
List all containers (running and stopped):
```
docker ps -a
```

Setting Container Names and Tags

Set a custom container name:

sudo docker run --name Thanos_of_2019 docker/whalesay cowsay I'm-Inevitable!

Specify an image version (tag):
```
sudo docker run nginx:1.14-alpine
```

Run multiple instances from the same image:

sudo docker run docker/whalesay cowsay Infinity-and-beyond!
sudo docker run docker/whalesay cowsay Hello-there!
sudo docker run docker/whalesay cowsay Cowabunga!

Pulling Images

To pull an image to your host (without running a container):

sudo docker pull <image-name>
sudo docker pull nginx

Managing Containers

Stop a running container:

docker stop <container-name>
docker stop <container-id>

Remove a container:
```
docker rm <container-name>
```
Forcefully remove a running container:
```
docker rm -f <container-name>
```
Remove all containers:
```
docker rm -f $(docker container ls -aq)
```
Remove all stopped containers without confirmation:
```
docker container prune -f
```
Delete stopped containers, unused images, and build cache:
```
docker system prune
```

Removing Images

Remove an image (ensure no containers are using it):
```
docker rmi <image-name>
```
Remove all images without associated containers:
```
docker image prune -a -f
```

Container Lifecycle

Containers are designed to run specific tasks or processes. When the task completes, the container exits. For example, running Ubuntu:

sudo docker run ubuntu

To run a process (like sleeping for 60 seconds):

sudo docker run ubuntu sleep 60

Executing Commands in Running Containers

To execute a command in a running container:

sudo docker exec <container-id> <command>
sudo docker exec <container-name> <command>

For example, to view the hosts file of a running container:

sudo docker exec <container-id> cat /etc/hosts
sudo docker exec <container-name> cat /etc/hosts

Docker commands​

Creating and Starting Containers​

Listing Containers​

Setting Container Names and Tags​

Pulling Images​

Managing Containers​

Removing Images​

Container Lifecycle​

Executing Commands in Running Containers​