CompTIA Linux+ XK0-006 (V8) Practice Question

The docker system prune sub-command is designed to clean up multiple object types in a single operation. By default it removes stopped containers, unused networks, dangling images and build cache, and it always prompts for confirmation unless --force is supplied. Adding the --volumes flag extends the cleanup to anonymous volumes that are not used by any container. Because the command is executed without the -a/--all flag, only dangling (untagged) images are removed; all tagged images remain, even if no container is currently using them.

• docker system prune --volumes therefore meets every requirement.
• docker system prune -a --volumes would additionally delete all unused images-including tagged images that become unreferenced after the stopped containers are removed-so it is too aggressive.
• docker volume prune touches volumes only and leaves containers and images in place.
• docker image prune -a removes images but leaves containers and volumes untouched.

For these reasons, the correct choice is the command that uses docker system prune --volumes.