segy2grd(1gmt) on Linux
The text 45b9fd77dfb7, as Debian 5.0 (Lenny) shipped it.
Converting SEGY file to grid file format
Flags it lists
-
-A -
-D -
-F -
-G -
-I -
-L -
-M -
-N -
-R -
-S -
-V -
-X -
-Y