I often use
open . to open the current folder from Terminal.app. From time to time this doesn't work. The reason is that the folder in question is already open in some other Finder window on some other Space.
Hunting down this Finder window by searching all spaces takes too long. Neither do I really want to go a different space. I just want to open a new Finder window right there on the current space, regardless of other Finder windows open anywhere else.
open -n . but this just hangs.