Which command is used to tag a Docker image before pushing it to a repository?

The command used to tag a Docker image before pushing it to a repository is "docker image tag." Tagging an image is an important step in Docker workflows because it allows you to assign a meaningful identifier to a Docker image. This identifier often includes the repository name and version, which helps in organizing and versioning images correctly in a Docker registry.

When you tag an image, you're essentially creating a new reference (tag) for an existing image, which allows you to update or maintain multiple versions of the same base image. This tagging process is crucial, especially in continuous integration and deployment scenarios, where managing different iterations of images becomes necessary.

Using the correct tagging command ensures that when you later push the image to a repository, the image is correctly referenced and easily retrievable based on its tag. It helps you and other users understand the version and purpose of the image upon examination.

In contrast, the other options listed do not fulfill the purpose of tagging an image:

• "docker image push" is used to upload an image to a repository but does not tag it.

• "docker container tag" is not a recognized command; the correct command applies to images, not containers.

• "docker repo tag" is not a valid Docker command for tagging images