nc(1) on OpenBSD
The text 47d098b35d52, as OpenBSD 3.5 shipped it.
arbitrary TCP and UDP connections and listens
Flags it lists
-
-4 -
-6 -
-S -
-U -
-X -
-d -
-h -
-i -
-k -
-l -
-n -
-p -
-r -
-s -
-t -
-u -
-v -
-w -
-z