bsmtp(8) on Linux
The text db72c03168e2, as Debian 3.0 (Woody), Debian 2.2 (Potato) shipped it.
append mail to bsmtp batch
Flags it lists
-
-B -
-C -
-F -
-G -
-T -
-U -
-d -
-f -
-s -
-t