The sudo usermod -aG docker jenkins command adds the user jenkins to the docker group. This is often done when you want the Jenkins automation server to have the ability to interact with Docker, such as running Docker containers as part of your CI/CD (Continuous Integration/Continuous Deployment) pipeline.

Here's a breakdown of the command:

• sudo: This command is used to run the following command as the superuser or with elevated privileges.

• usermod: This command is used to modify user account properties.

• -aG: These are options for the usermod command:

  • -a: It appends the user to the specified group(s) without removing them from any existing group.

  • -G: It specifies the group to which the user should be added.

• docker: This is the name of the group to which jenkins will be added. The docker group typically allows users to run Docker commands without needing to use sudo.

• jenkins: This is the username of the user being added to the docker group.

Conclusion

After running this command, the user jenkins will have the necessary permissions to run Docker commands without needing to use sudo. This can be useful if your Jenkins server needs to build and deploy Docker containers as part of your automated CI/CD process. However, keep in mind that adding a user to the docker group grants them significant privileges, so ensure that this is done with care and for trusted users only.