r.spread(1grass) on Linux
The text 227d9c7e5588, as Debian 4.0 (Etch) shipped it.
Simulates elliptically anisotropic spread on a graphics window and generates a raster map of the cumulative time of spread, given raster maps containing the rates of spread (ROS), the ROS directions and the spread origins. It optionally produces raster maps to contain backlink UTM coordinates for tracing spread paths.