Top 10 Docker Commands You Need to Know

Docker has changed the goalposts of application development and deployment by providing a standard environment to run the applications, which is independent of their place of deployment. Moving forward into 2024, as a developer and DevOps engineer, one has to fully understand and know how to use appropriately the basic Docker commands. This article gives step-by-step explanations of the top 10 Docker commands with descriptions, syntax, examples, and advantages.

What is Docker?

Docker is an open-source platform for automating deployment, scaling, and management of applications that packages an application with all its dependencies into a single unit called a container. With this base, the containers will run consistently on any computing environment; therefore, Docker is a key tool in modern software development.

Advantages of Using Docker Commands

• Across Environments: Docker containers make it possible to run applications in the same manner across all types of environments, mitigating issues related to environment differences.
• Resource Efficiency: The containers are light in weight and the kernel of the host system is shared with other containers. This results in lesser usage of resources in comparison to the traditional virtual machines.
• Scalability: A main advantage of Docker is obvious in the easy scalability of applications with its use, by easily starting, stopping, or duplicating containers.
• Portability: Docker containers are easily portable across different environments or cloud platforms, increasing flexibility and portability.

Top 10 Docker Commands You Need to Know

Let’s dive deeper into each of these essential Docker commands and understand how they can be used to optimize your container management.

1. docker run

The docker run command allows for the creation and launch of a new container based on a given Docker image. With this functionality, one may configure network settings, volumes, or environment variables for the container.

Syntax:

docker run [OPTIONS] IMAGE [COMMAND] [ARG...]

Example:

docker run -d -p 80:80 nginx

Advantages:

• Quick Deployment: It helps in quick deployment of applications by launching containers from pre-existing images.
• Configuration Flexibility: Options allow for detailed control over container behavior and environment.
• Isolation: Runs applications in isolated environments, reducing the risk of conflicts.

2. docker ps

You will see a listing of all the running containers on your Docker host with the docker ps command. This is very useful information about the containers, showing things like their IDs, names, status, and port mappings.

Syntax:

docker ps [OPTIONS]

Example:

docker ps -a

Advantages:

• Monitoring : You get to monitor the state and status of all containers, both running and stopped.
• Troubleshooting: Useful for identifying running containers that may need attention or maintenance.

3. docker images

The docker images is downloaded from a public or private registry like Docker Hub using the docker pull command. This will have already been demonstrated as it's normally the precursor to creating a container from an image that isn't already available locally.

Syntax:

docker images [OPTIONS] [REPOSITORY[:TAG]]

Example:

docker images

Advantages:

• Image Management: This screen provides an overview of available images, including their tags and sizes.
• Disk Space Management: It aids in detecting the removal of unused images to recover memory space on the disk.

4. docker pull

The docker pull command is used to download a Docker image from a public or private registry, such as Docker Hub. This is typically the first step in creating a container from an image that is not already available locally.

Syntax:

docker pull [OPTIONS] NAME[:TAG|@DIGEST]

Example:

docker pull ubuntu:latest

Advantages:

• Pre-built Images: Access to pre-built images is very easy from registries and thus saves a lot of time and effort in building images from scratch.
• Version Control: This allows you to target specific versions or tags, thus ensuring you are executing the appropriate version of your image.

5. docker stop

The docker stop command stops a running container by sending a SIGTERM signal, allowing processes inside the container to terminate gracefully.

Syntax:

docker stop [OPTIONS] CONTAINER [CONTAINER...]

Example:

docker stop <container_id>

Advantages:

• Graceful Shutdown: This ensures that all containers are stopped correctly to avoid data loss or corruption.
• Resource Management: It frees up the system resources by stopping containers that are not required anymore.

6. docker rm

The docker rm command removes one or more stopped containers from your system. This is useful for cleaning up containers that are no longer in use.

Syntax:

docker rm [OPTIONS] CONTAINER [CONTAINER...]

Example:

docker rm <container_id>

Advantages:

• System Cleanliness: It cleans up the Docker environment by removing unused containers.
• Free up resources: Delete containers no longer needed, thereby releasing storage and memory.

7. docker rmi

The docker rmi command is used to remove Docker images from your local system. It’s essential for managing disk space and cleaning up unused images.

Syntax:

docker rmi [OPTIONS] IMAGE [IMAGE...]

Example:

docker rmi ubuntu:latest

Advantages:

• Disk Space Management: It can help manage disk space because images that are not needed anymore may be deleted.
• Image Cleanup: This feature only stores necessary images to your locals, reducing clutter.

8. docker logs

The docker logs command retrieves the logs from a running or stopped container. It’s a vital tool for troubleshooting and monitoring containerized applications.

Syntax:

docker logs [OPTIONS] CONTAINER

Example:

docker logs <container_id>

Advantages:

• Troubleshooting: It helps identify problems by displaying verbose logs from within the container.
• Monitoring: This is one method to view the output of containers that are running in real time.

9. docker exec

The docker exec command runs a command inside a running container. This is useful for executing tasks within the container, such as running a shell or executing a script.

Syntax:

docker exec [OPTIONS] CONTAINER COMMAND [ARG...]

Example:

docker exec -it <container_id> bash

Advantages:

• Interactivity: Since users are allowed to interact with a running container, it is useful to have for debugging and maintenance purposes.
• Flexibility: Run any command that you want in a container without having to bring it down.

10. docker-compose up

The docker-compose up command is used to start all services defined in a docker-compose.yml file. This command is key for managing multi-container Docker applications.

Syntax:

docker-compose up [OPTIONS] [SERVICE...]

Example:

docker-compose up -d

Advantages:

• Manage and easily orchestrate numerous containers that are defined in a Docker Compose file.
• Automation: Provides automation of setup for complex environments, cutting down on manual configuration and errors.

Must Read

• What is Docker?
• OpenShift vs Docker - What are the differences?
• How To Install Docker Engine On AWS Debian Linux Server

Conclusion

All these commands in Docker, internalized, will make your handling of containers and images better in 2024. Therefore, whether a developer will make their workflow smoother, or a DevOps professional will make the application deployment efficient, the knowledge of such commands forms the basis of working with Docker. Describing those, syntaxes, examples, and its benefits will make sure that with this knowledge, you make and are sure the Docker environment you are in is well managed, clean, and highly optimized in performance.