baresip(1) on Linux
The text 5d278c065315, as Debian 10 (Buster) shipped it.
portable and modular command-line SIP user-agent
Flags it lists
-
-6 -
-? -
-d -
-e -
-f -
-h -
-m -
-n -
-p -
-t -
-u -
-v