$: docker images -a
REPOSITORY TAG IMAGE ID CREATED SIZE
<none> <none> fbc7da749948 2 hours ago 180MB
<none> <none> a7ab17d3bd01 2 hours ago 180MB
<none> <none> a20b38f75d61 2 hours ago 180MB
<none> <none> 40d335919b18 2 hours ago 180MB
<none> <none> 44d8d1d61a61 2 hours ago 180MB
<none> <none> 340f2bcd4ba7 2 hours ago 180MB
openvpn-serv latest d5dfd7db7d9a 2 hours ago 180MB
<none> <none> 75e59c0dd9bb 2 hours ago 180MB
<none> <none> e64dcdc5e4f6 2 hours ago 180MB
ubuntu latest b1d9df8ab815 4 weeks ago 78.1MB
$: docker rmi $(docker images -f "dangling=true" -q)
"docker rmi" requires at least 1 argument.
See 'docker rmi --help'.
Usage: docker rmi [OPTIONS] IMAGE [IMAGE...]
Remove one or more images