# [Docker] Tips

# 1. Image operations:

### 1.1 Build an image if you've already written a Dockerfile

## run the following command in the folder containing Dockerfile
docker build -t imageName:imageTag

### 1.2. List all images

docker images


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### 1.3. Save and load image:
Step1. Save a Docker Image as a compressed file.

$ docker save mytomcat -o mytomcat.tar


Step2. Put this compressed file to the other computational resource, and then load it to docker.

$ docker load -i mytomcat.tar


Resource:
a. https://ithelp.ithome.com.tw/articles/10191387
b. https://www.twblogs.net/a/5cc16cf6bd9eee397113f7a7

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# 2. Container operations

### 2.1. Basic operations

## 2.1.1 stop a container
docker stop containerID

## 2.1.2 restart a container if it exited
docker restart containerID

## 2.1.3 execute a container if it exists
docker exec -it containerID /bin/bash

## 2.1.4 remove a exited container
docker rm containerID

### 2.2. List all existed containers

docker ps -a


Without **-a** option, only running containers will be shown.

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### 2.3. Remove all existing containers

docker rm $(docker ps -a -q)

[Reference](https://www.freecodecamp.org/news/how-to-remove-images-in-docker/)

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## Advenced

### Run Multiple Commands through one line docker command:
We can use the -c option with the shell to execute multiple commands simultaneously. The sh -c option allows us to pass a string containing multiple commands as an argument. Let's run the whoami and date commands using sh -c:

docker run centos:latest sh -c "whoami && date"

[Reference](
https://www.baeldung.com/ops/docker-run-multiple-commands)

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### Mount nfs to docker container:
Make sure *nfs-common* has been installed.

docker run --rm -it --mount type=bind,source=<your nfs folder>,target=<which folder you want to mount in container> <your_image_name>

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user group
https://docs.docker.com/engine/install/linux-postinstall/

###### tags: `docker`