You have already used the docker --version command as a quick test to confirm that Docker was installed. Now try the command without the dashes:
docker version
This version of the command gives you greater detail about the version of Docker installed on your system. It is worth noting that the docker-compose command, which we will talk about later, also has two versions of the version command—one with the dashes providing a single-line response, and one without the dashes that delivers more details.
Remember that all the Docker commands have a rich help system built in. Try it by entering any part of a Docker command and using the --help parameter. For example, docker container run --help.