Thanks Michael for not slamming me. I've looked into Bit::Vector and Bit::ShiftReg however I don't think they will do what I need done. That being said I could be totally wrong. Truthfully I don't know where to look. I've searched the modules for anything with LRS or registers but haven't seen anything I think will work. I have other tools that will do this (C code), however I didn't write them and they can only handle up to 2 Gigs. The file I have is 9 Gigs. Although a bit slow I can get perl to handle that big of a file. I'm not looking for someone to do the work for me, I'm just looking to be pointed in the right direction.