manage docker images

• don’t want to run $ docker image prune -a because there are ad hoc images that are used occasionally.

# sort by registry name

$ docker image ls | sort

# sort by tags & delete old versions by registry name

$ docker image ls --format="{{.Tag}}\t{{.ID}}\t{{.Repository}}" |
    sort |
    grep <name> |
    cut -f 2 |
    tr '\n' ' ' |
    sed 's/ $/\n/'

All references except the last one can be deleted.