This question is an exact duplicate of:
Is it possible to generate a styled KML using ogr2ogr (ie pen width and colour?) I cannot seem to find anything in the ogr2ogr documentation.
My code so far is;
ogr2ogr.exe -f "KML" prow-kml.kml "C:\prow.shp"
Unfortunately this just gives me a default colour line when viewing in Google Earth.