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Typically, when most developers start using docker, after going through all the processes of pulling images, building them, and running containers, removing a container defeats the purpose of doing so. However, for experienced developers, this brings benefits that help develop applications and make them as efficient as possible.

This article will discuss the use of rm command in docker. In addition, you will also understand the advantages of using this command.

Pull an Nginx image

In this tutorial, you will use the Nginx image. You can also use any image from docker hub.

So, open a new terminal (keyboard shortcut Ctrl+Alt+T) and use the command below to pull the image.

~$ docker pull nginx:alpine

Output:

alpine: Pulling from library/nginx
ca7dd9ec2225: Already exists
76a48b0f5898: Pull complete
2f12a0e7c01d: Pull complete
1a7b9b9bbef6: Pull complete
b704883c57af: Pull complete
4342b1ab302e: Pull complete
Digest: sha256:455c39afebd4d98ef26dd70284aa86e6810b0485af5f4f222b19b89758cabf1e
Status: Downloaded newer image for nginx:alpine
docker.io/library/nginx:alpine

Run a container from an image

After downloading the image, run the container named temp-container using the following command.

~$ docker run --rm --name temp-container -w /com/app/ nginx:alpine pwd

Output:

/com/app

In docker runthe command, you used the --rm flag, which automatically removes the container when it exits. You also used the -w flag to set the working directory in the container.

Additionally, the container's working directory is printed using the pwd command. Typically, this command runs the container, sets the container's working directory, and removes the container via the --rm flag after printing the working directory.

Since the main purpose of running this container is to test whether the working directory is set successfully, there is no need for a container on the host machine, so the container is deleted.

This is one of the use cases for the --rm flag. The benefit of using this command is that you can save computer storage space used by unused containers.

To verify that this command has been removed, check if the container exists using the following command.

~$ docker ps -a

Output:

CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES

If you have other running containers inside the container, they will all be listed with the above command. However, if you have no other containers, nothing will be listed on the console.

Finally, another advantage of using the --rm flag is that it helps us automate cleanup and proof of concept.

Summarize

Use this command only for short-lived containers, especially those used for testing purposes. In conclusion, this article showed you how to use the --rm flag and why to run a container with this command.

Finally, you learned some of the benefits of using this command.