xyz2grd(1gmt) on Linux
The text 39fd8d785d48, as Debian 7 (Wheezy) shipped it.
Converting an ASCII or binary table to grid file format
Flags it lists
-
-: -
-A -
-D -
-E -
-F -
-G -
-H -
-I -
-N -
-R -
-S -
-V -
-Z -
-bi -
-f