I'm attempting to replace the same sequence of hex bytes with a different sequence in multiple files. I've been able to do this for individual files using Hex Fiend, but would like to be able to run a script or command to edit all files of the same type in a folder. I've tried using the sed and tr commands, but they don't seem to want to find/replace multiple hex bytes. I want to do this to change the header of the RAW files from my Sony A850 camera, which are still unsupported in Aperture and Mac OS. If I change the identifiers in the header, the files will be accepted as A900 RAW files and work fine (the cameras have identical sensors). Ultimately, I need to replace the sequence "38 35 30" with "39 30 30" in 3 locations for each file.