grdedit(1gmt) on Linux
The text 0f34d8dade7c, as Debian 8 (Jessie), Debian 7 (Wheezy), Debian 6.0 (Squeeze), Debian 5.0 (Lenny), Debian 4.0 (Etch), Debian 3.1 (Sarge) shipped it.
Modifying the header in a 2-D grdfile
Flags it lists
-
-A -
-D -
-R -
-S -
-V