RegDiff

It is a small command line tool to compare two registry files, export the registry, merge .REG files and much more. regdiff.exe is freeware with a very liberal BSD-style license (i.e. free for any use including commercial). Features: -Compare, diff and merge .REG files -Compare, diff and merge the registry -Support for both ANSI and UNICODE style .REG files -It's free!