grdrotater(1gmt) on Linux
The text 1cec2bae89c2, as Debian 4.0 (Etch) shipped it.
Rotate a grid using a finite rotation
Flags it lists
-
-: -
-F -
-G -
-H -
-M -
-N -
-Q -
-R -
-S -
-T -
-V -
-bi -
-bo