he “docker ps” command is used to list all the running containers in the docker host. With the help of some filters, you can get the output of all the containers in the docker with are running and that are stopped. it shows the list of active containers that includes details about each one, including its name, ID, creation image, program being run inside it, creation time, and status.
“docker ps” Command Complete Step-By-Step Guide
The “docker ps” command will guide us in the docker host by listing all the docker containers. It will list all the docker containers in the docker host.
Sytanx Of “docker ps” Command Without Options
1. Here we will execute the docker ps command without any option or filters and let’s see the output we are getting.
docker psIn the above image, you can see the no.of docker containers that are running inside the docker host “docker ps” command will give us the output of the following.
- Container ID.
- Images that have been used to run the container.
- The command which is used to start the container where we will mention it in the Dockerfile.
- Status of the container.
- ports used to expose the docker container.
Sytanx Of “docker ps” Command With Options
By using multiple options you can perform multiple tasks in the docker host as shown follows.
docker ps <option>
To see all the containers in the docker including the containers which have been exited you use the following command.
docker ps -a“-a” or “–all” can be used along with the docker command.
“docker ps” Commands With Different Options
You can us the docker ps command with different options which will give us the output depending on the output required.
|
Command |
Options |
|---|---|
|
docker ps “- q” or “–quite” |
Show only the container IDs. |
|
docker ps “– format” |
Specify a Go template to format the output. |
|
docker ps “– filter” |
Filter output based on conditions. |
‘docker ps’ vs ‘docker container ls’
There is no much difference in between the docker ps and docker container ls as shown in the image below.
- docker container ls: This command lists all the currently running containers. The output shows one container with the following details:
- CONTAINER ID: 1041a2d84eff – This is the unique identifier for the container.
- IMAGE: nginx – This indicates that the container is running an nginx image, which is commonly used as a web server or reverse proxy.
- COMMAND: “/docker-entrypoint…” – This is the command that was used to start the container, and it has been truncated in the display. The full command is likely something like “/docker-entrypoint.sh nginx -g ‘daemon off;'”, which is the default command for nginx Docker images.
- CREATED: 57 minutes ago – The container was created 57 minutes before the command was run.
- STATUS: Up 57 minutes – This shows that the container has been running since it was created.
- PORTS: 80/tcp – The container has exposed port 80 for TCP traffic, which is the standard port for HTTP web services.
- NAMES: adoring_bell – Docker has automatically assigned a whimsical name to the container, in this case, “adoring_bell”.
- docker ps: This is an older command that serves the same purpose as docker container ls, which is to list all running containers. It’s commonly used for its brevity and gives the same output as docker container ls.
The output for both commands is identical, showing that there is one running container based on the nginx image. The fact that the commands have been run in sequence with identical output suggests that there has been no change in the status of running containers between the execution of the two commands. The container seems to be running normally, but without additional context, it’s not possible to determine what service it is providing or if it is part of a larger application or service.
Conclusion
In conclusion the command docker ps is an effective tool for handling Docker containers. With vital details like container IDs, image names, status, and ports, it enables users to display every container that is currently executing on their Docker host. This command is essential for effectively administering containerised applications, keeping an eye on container activity, and diagnosing problems.
“docker ps” Command – FAQ’s
What is P and P in docker?
- -p (lowercase p): This flag allows you to explicitly publish a single port or a range of ports from the container to a specific port or range of ports on the host machine. It provides granular control over how you expose container ports.
- -P (uppercase P): This flag stands for publish-all. It’s a shortcut that instructs Docker to publish all exposed ports within the container to random ports on the host’s interfaces. This is a convenient option but can be less secure and predictable compared to -p.
What is the flag in docker ps?
The –format flag in docker ps allows you to customize the output using Go template strings. This lets you define exactly which information about the containers you want to see and how it’s formatted.
How do I list all docker images?
This is the simplest and most common approach. The command docker images (or docker image ls which is an alias) will list all images currently available on your Docker host.