docker system prune --help

Usage:  docker system prune [OPTIONS]

Remove unused data

Options:
  -a, --all             Remove all unused images not just dangling ones
      --filter filter   Provide filter values (e.g. 'label=<key>=<value>')
  -f, --force           Do not prompt for confirmation
      --volumes         Prune volumes

See also

• docker system: docker system info , docker system events , docker system df, docker system prune -a

https://docs.docker.com/v17.12/edge/engine/reference/commandline/system_info/

https://docs.docker.com/v17.12/edge/engine/reference/commandline/system_events/