Existing docker images can be found at existing images at registry.hub.docker.com/ or Run the command on the terminal docker search linux
The Docker CLI has a command called run which will start a container based on a Docker Image. The structure is docker run .
By default, Docker will run a command in the foreground. To run in the background, the option -d needs to be specified.
By default, Docker will run the latest version available. If a particular version was required, it could be specified as a tag, for example, version 3.2 would be docker run -d redis:3.2
Docker first search the image locally and if not found than it searches the docker registery hub directory.