In my earlier articles we have seen how to install docker and docker compose. If you missed the part, please check the links for installing docker and docker compose.

In this article we will see how to work with docker in brief.

The first basic command to check your docker installation by running a simple docker image on your system.



What is a docker image:

    Docker image is an application available on docker cloud. We can run the image directly or we can download and execute it. Now we will download an image called Busybox from docker cloud and run it.

The command used to download the docker image is docker pull image_name.


If you face permission denied issue try executing with sudo.



To list the downloaded images use docker images command. It will give you the details of the image size,ID and image created day.



Running the docker image:`

    We can directly run the docker image by run command but anyway the image will be downloaded to the system. These images runs in a virtual environment called as docker container. Each container has an unique ID.



Checking the status of your containers:

    The command ps with the flag -a will list all the containers either it is running or in exited state.


The above commands will give the

• Container ID
• Image Name
• Command Used
• Container created time
• Status of the container
• Port number
• Names

Getting into a container:

    Since we are not getting into OS level, the busybox and hello-world are just a simple application and it just executes the command we pass. So the status are showing as Exited.

    If we are executing the commands by logging into the container then the container status will be shown as UP.

   So to get into a container we need to add i and t flag while executing run command with shell.



Accessing a Running container:

    The run command with -it flag will create a container and gets log into it. If we want to access a running or existing container we need to use exec command following with the Container_ID.



    Run ps command on different tab so you can check the status of a running container.



Stopping a container:

The command docker stop Container_ID will stop the running container.


Deleting the container:

    To delete a container we can use rm command following with the container's ID. The container can be deleted only when it is in exited status.


If we are having n number of containers in our system , we can filter it by querying its status. So it would be easy for us to delete them.

To list the stopped container:


To list the running container:


Deleting all stopped containers:

    After listing the stopped containers we can delete the one we are not going to use. If we want to delete all the stopped containers we can use prune command.



Deleting a docker image:

    The command rmi used to delete a docker image. To delete a image the below things should be checked.

1. The image should not be used by any running container.
2. Image can be deleted only by its ID and not by its name.

That's it for a total startup. We will see creating a docker image and dive deep on the upcoming articles. Feel free to ask if you have any questions.