What is the Docker CLI, and How is it Used?

The Docker Command Line Interface (CLI) is a powerful tool that allows users to interact with the Docker daemon and manage Docker containers, images, networks, and volumes. The CLI provides a set of commands that enable users to perform various operations related to containerization, making it an essential component for developers and system administrators working with Docker.

1. Overview of Docker CLI

The Docker CLI is typically accessed through a terminal or command prompt. It communicates with the Docker daemon, which is responsible for managing Docker containers and images. The CLI commands are structured in a way that allows users to create, manage, and monitor containers and images efficiently.

2. Common Docker CLI Commands

Here are some of the most commonly used Docker CLI commands:

2.1. docker run

The docker run command is used to create and start a new container from a specified image.

Example: Running a Container

docker run -d --name my_container nginx

In this example:

• -d: Runs the container in detached mode (in the background).
• --name my_container: Assigns a name to the container.
• nginx: Specifies the image to use (in this case, the official Nginx image).

2.2. docker ps

The docker ps command lists all running containers. You can add the -a flag to see all containers, including stopped ones.

Example: Listing Running Containers

docker ps

Example: Listing All Containers

docker ps -a

2.3. docker images

The docker images command lists all available images on the local system.

Example: Listing Docker Images

docker images

2.4. docker rm

The docker rm command is used to remove one or more stopped containers.

Example: Removing a Container

docker rm my_container

2.5. docker rmi

The docker rmi command removes one or more images from the local system.

Example: Removing an Image

docker rmi nginx

2.6. docker logs

The docker logs command retrieves the logs from a specified container, which is useful for debugging and monitoring.

Example: Viewing Container Logs

docker logs my_container

2.7. docker exec

The docker exec command allows you to run commands inside a running container.

Example: Running a Command in a Container

docker exec -it my_container /bin/bash

In this example, the -it flags are used to run an interactive terminal session inside the container.

3. Conclusion

The Docker CLI is a powerful and essential tool for managing Docker containers and images. By using the various commands available in the CLI, users can efficiently create, manage, and monitor their containerized applications. Mastering the Docker CLI is crucial for anyone working with Docker, as it provides the flexibility and control needed to work effectively in a containerized environment.