I have forty years of data in the form of one raster per day. I am hoping to aggregate these rasters so that I get one raster per month. To avoid aggregating thousands of files by hand, I would like to aggregate the files using their files names, which are in the form "TOMS_YEARmMONTHDAY_v8.HDF" (i.e. "TOMS_1976m0105_v8.HDF" for January 5, 1976). Would you please let me know if you have any guidance as to how exactly I might do this? Thanks so much.