Gravity(1) on Linux
The text ea473da44e02, as Debian 10 (Buster) shipped it.
Flags it lists
-
--comment-delimiter -
--help -
--input-file -
--input-string -
--line-separator -
--output-file -
--version -
-A -
-D -
-G -
-H -
-d -
-h -
-n -
-p -
-v -
-w