Beginner's Guide to Docker

If you're new to Docker and looking for a practical, beginner-friendly tutorial to understand the core commands used to run, inspect, and manage containers and images, this guide is exactly what you need.

In this hands-on walkthrough, we'll cover:

How to run Docker containers
How to interact with and inspect them
How to manage Docker images
How to clean up unused containers and images

🛠️ Prerequisites

Docker must be installed and running on your machine.
Basic knowledge of terminal/command line usage.

You can check if Docker is installed by running:

docker --version

🚀 Step 1: Pull an Image

Start by pulling the official nginx image from Docker Hub:

docker pull nginx

This command downloads the nginx image locally so you can use it to run containers.

📂 Step 2: Run a Container in Detached Mode with a Name

Now create and start a container from the nginx image:

docker run -d --name mynginx nginx

Explanation:

-d: Detached mode (runs in background)
--name mynginx: Assigns a custom name to the container
nginx: Name of the image to use

Verify it's running:

docker ps

This will show running containers with details like Container ID, image, status, and ports.

💻 Step 3: Access the Container's Shell

To enter an interactive shell inside the running container:

docker exec -it mynginx /bin/bash

If /bin/bash doesn't work (for Alpine-based images), use:

docker exec -it mynginx /bin/sh

Once inside, try commands like:

ls
hostname

Exit the container shell:

exit

🔎 Step 4: Inspect Container Details

To view detailed information about a container (in JSON format):

docker inspect mynginx

To fetch specific info, like the IP address:

docker inspect -f '{{ .NetworkSettings.IPAddress }}' mynginx

This is helpful for debugging or checking network configurations.

🧱 Step 5: View Image History

To see the history of commands that built a Docker image:

docker history nginx

This shows each layer added to the image, including commands like FROM, COPY, and RUN.

🚳 Step 6: Stop and Remove a Container

To stop a running container:

docker stop mynginx

Then remove it:

docker rm mynginx

To remove the nginx image:

docker rmi nginx

🚮 Bonus: Clean Up Commands

📊 List Containers and Images

docker ps            # running containers
docker ps -a         # all containers (including stopped)
docker images        # all local images

🗙️ Remove All Stopped Containers

docker container prune

Or:

docker rm $(docker ps -a -q)

📃 Remove All Unused Images

docker image prune

Or:

docker rmi $(docker image ls -q)

Use with caution: These will free up space but delete unused content.

🔼 Recap: Key Commands Summary

Task	Command Example
Run a container	`docker run -d --name name image`
Access container shell	`docker exec -it container /bin/bash`
Inspect container details	`docker inspect container_id`
Show image layers	`docker history image_id`
List running containers	`docker ps`
List all containers	`docker ps -a`
List images	`docker images`
Stop container	`docker stop container_id`
Remove container	`docker rm container_id`
Remove image	`docker rmi image_name`
Prune all stopped containers	`docker container prune`
Prune all unused images	`docker image prune`

🎉 You're Ready to Docker!

Congratulations! You’ve now taken your first steps with Docker containers and images. This hands-on experience will help you understand containerized workflows used in real-world DevOps, development, and deployment pipelines.

If you enjoyed this guide, share it with your fellow developers or leave a comment with what you'd like to learn next!

Happy Dockering! 🐳

🐳 Getting Started with Docker: A Hands-on Guide for Beginners