rdate(8) on Linux
The text 8bd6e64dcbc8, as Debian 11 (Bullseye) shipped it.
set the system's date from a remote host
Flags it lists
-
-4 -
-6 -
-a -
-b -
-c -
-n -
-o -
-p -
-s -
-t -
-u -
-v