nc(1) on OpenBSD
The text 31fda9825c43, as OpenBSD 4.8 shipped it.
arbitrary TCP and UDP connections and listens
Flags it lists
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-4 -
-6 -
-D -
-I -
-O -
-P -
-S -
-T -
-U -
-V -
-X -
-d -
-h -
-i -
-k -
-l -
-n -
-p -
-r -
-s -
-t -
-u -
-v -
-w -
-z