Guiffy is a File Compare Diff tool, Merge tool, and Folder compare tool  all-in-one. Its cross-platform, comes with a command line interface, and includes an API package. Guiffy recognizes over 150 source file encoding formats. And, Guiffy's Trustworthy 3-way merge, SureMerge, was designed from day 1 to avoid all the problems that plague other 3-way diff based merge tools.