docker tag | Docker Documentation
docs.docker.com › engine › referenceA tag name must be valid ASCII and may contain lowercase and uppercase letters, digits, underscores, periods and dashes. A tag name may not start with a period or a dash and may contain a maximum of 128 characters. You can group your images together using names and tags, and then upload them to Share images on Docker Hub.
docker images | Docker Documentation
docs.docker.com › engine › referenceList images by name and tag. The docker images command takes an optional [REPOSITORY[:TAG]] argument that restricts the list to images that match the argument. If you specify REPOSITORYbut no TAG, the docker images command lists all images in the given repository. For example, to list all images in the “java” repository, run this command :