nsupdate(1) on Linux
The text 9a87ddfbfffd, as Debian 11 (Bullseye) shipped it.
dynamic DNS update utility
Flags it lists
-
-4 -
-6 -
-D -
-L -
-P -
-T -
-V -
-d -
-i -
-k -
-l -
-p -
-r -
-t -
-u -
-v -
-y