ssh-add(1) on macOS
The text 090a34d3e0c1, as Mac OS X 10.8.5, Mac OS X 10.8.4, Mac OS X 10.8.3, Mac OS X 10.8.2, Mac OS X 10.8.1, Mac OS X 10.8 shipped it.
adds private key identities to the authentication agent
Flags it lists
-
-D -
-K -
-L -
-X -
-c -
-d -
-e -
-k -
-l -
-s -
-t -
-x