grfmerge (1) Linux Manual Page
GRFMerge – A tool to apply a binary GRF diff, generated by GRFDiff, to a GRF. Synopsisgrfmerge [-hlyv ] GRD-file [GRF-file ] Change sprites in the GRF file to the new ones from the GRD file. If the GRF file is not specified, GRFMerge will modify the one which the GRD file was generated from….
