This question explains how to stop Docker containers started from an image.
But if there are no running containers I get the error docker stop requires a minimum of one argument. Which means I can't run this command in a long .sh script without it breaking.
How do I change these commands to work even if no results are found?
docker stop $(docker ps -q --filter ancestor="imagname")
docker rm `docker ps -aq` &&
(I'm looking for a pure Docker answer if possible, not a bash test, as I'm running my script over ssh so I don't think I have access to normal script tests)