"Short" trailer testfiles

def shaveOrbitTrailer(ifile):
    fout = open(ifile.replace(".dat", "_short_trailer.dat") ,'wb')
    if ifile != 'stdin':
        fin = open(ifile, 'rb')
    else:
        fin = sys.stdin.buffer

    try:
        while True:
            h_raw = fin.read(4)
            if (len(h_raw)==0):
                print('Reached end of file')
                fin.close()
                break

            if struct.unpack('<I', h_raw)[0]==0xbeefdead:
                print("Orbit trailer found", hex(struct.unpack('<I', h_raw)[0]))
                otrailer = h_raw + fin.read(4*(7+15*8))
                fin.read(4*8)
                fout.write(otrailer)
                continue

            frame = h_raw + fin.read(4*7)
            fout.write(frame)
    except Exception as ex:
        print(f"exception: {ex}")
        sys.exit(1)