Docker Commands

Introduction to Docker Commands

Docker implies OS-level virtualization. Most developer prefers using docker and operating systems are tightly coupled with developers. Optimizing on the platform’s functionality kicks with docker commands mastery. They are very much lightweight VM’.

Basic Commands

Given below are the basic commands:

• docker –version – Display the current version.
• docker pull <image> – Docker repository images can be pulled using the docker pull command.

Example:

Code:

docker pull ubuntu

• docker run -it -d <image name> – For generating a container from an image.

Example:

Code:

docker run -it -d ubuntu

• docker ps -a – Displays running and exited containers.
• docker exec -it <container id> bash – Command for accessing running container.
• docker kill <container id> – Command for stopping the execution of a container immediately.

Example:

Code:

docker kill d61153bc

• docker commit <container id> <username/image name> – This command creates a new image of an edited container on the local system.
• docker push <username/image name> – This Docker command is used to push an image to the docker hub repository.
• docker images – Listing all images stored in a docker.
• docker rm <container id> – Deleting a container which has stopped execution.

Docker Intermediate Commands

Given below are the docker intermediate commands:

• docker checkpoint command – This Docker command is used for managing checkpoints.
• docker save [OPTIONS] IMAGE [IMAGE…] – Saving more than one image to tar archives.

Example:

Code:

docker save --output testbox.tar textbox

• docker search [OPTIONS] TERM – Searching docker hub for images.

Example:

Code:

docker search textbox

• docker stats [OPTIONS] [CONTAINER…] – Displaying resource usage statistics.

Example:

Code:

docker stats

• docker system command – It is Used for Managing a docker.

Command	Description
docker system df	Show docker disk usage.
docker system events	Get real-time events from the server.
docker system info	Display system-wide information.
docker system prune	Remove unused data.

• docker tag SOURCE_IMAGE[: TAG] TARGET_IMAGE[: TAG] – Creating a target image referring to a source image.

Example:

Code:

docker tag 0e5574283393 fedora/httpd:version1.0

• docker unpause CONTAINER [CONTAINER…] – Unpause all processes within one or more containers.

Example:

Code:

docker unpause test container

• docker import [OPTIONS] file|URL|- [REPOSITORY[: TAG]] – Importing contents from the tarball to create a system image of the file.
• docker info [OPTIONS] – Display system-wide information.

Example:

Code:

docker info -f

• docker logout [SERVER] – Logging out of a Docker registry.

Advanced Commands

Given below are the advanced commands:

• docker-machine upgrade default – To upgrade the docker to the latest version. How this upgrade happens depends on the underlying distribution used on the created instance.
• docker build –rm=false – Boolean options take the form -d=false. The value you see in the help text is the default value which is set if you do not specify that flag. If you specify a Boolean flag without a value, this will set the flag to true, irrespective of the default value.

Tips and Tricks to Use Docker Commands

• Use -f flag for activating the logging.

Example:

Code:

docker logs <containerid> -f

• JSON split can be achieved in docker by default; single keys can be extracted using jq.
• Package installations have to be taken increased care of as those commands are cached as well.
• There are a few places where one can specify commands in your Docker file.
• A cache will be invalidated by add when the files are changed.
• At the time of building the image, there is no use of writing to the volumes.
• All users are determined from the host; hence there is no user namespacing docker.
• Sudo helps to execute the commands.
• Starting a docker into execution is a comparatively easy process.
• Docker allows the creation of aliases for its own commands in a very effective manner. This helps to manage and handle long and really large commands. Files ~/.bashrcor ~/.bash_aliases holds the alias values.
• For reaching out containers accessed internally on a network, there is always a need to withhold the corresponding ID of the container; the command ps -a helps to get this archived.
• When a needed port is occupied on a different service, then for executing a container, the host port can be plugged into a specific container port.E.g. (host port 8080 to container port 50).
• Docker provides additional support to clean the unnecessary code bits from the deployment container.
• Its always set to pair the docker file associated to its respective run statements. This helps to solve problems as prescribed, excluding unnecessary disk space usage.
• Docker always prefers catching up on statements in the docker file that has not faced any change. Therefore, Time-saving can be achieved by setting the contents depicted in the docker file in an order where the least possible change contents are mentioned at the top, and more likely, change contents are depicted at the bottom of the file.

Conclusion

Though docker seems to be an easy setup, it’s actually a complex system to handle when considering its vibrant features into a picture. Definitely, Docker is among the popular virtualization tools and allows extremely coupled with the host operating system.

Recommended Articles

This has been a guide to Docker Commands. Here we have discussed basic, immediate as well as advanced docker commands respectively. You may also look at the following articles to learn more –

1. Advanced GIT Commands
2. List of Rails Commands
3. Basic C Commands
4. Bootstrap Commands