grdmath(1gmt) on Linux
The text 0c95eb3251af, as Debian 8 (Jessie), Debian 7 (Wheezy), Debian 5.0 (Lenny), Debian 4.0 (Etch), Debian 3.1 (Sarge) shipped it.
Reverse Polish Notation calculator for grd files
Flags it lists
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-F -
-I -
-R -
-V