Patch Viewer is a reliable application that can be used to view patch files (or the output from diff-like command-line tool) using your existing third-party graphical file comparison tool such as Xcode's FileMerge.
You can diff output in traditional, context and unified formats from a range of command-line source control tools such as Git, Subversion, Mercurial and CVS (to name a few) is supported.
Patch Viewer can also be used on the command-line to receive diff data piped into it as standard input.
NOTE: To buy Patch Viewer via the App Store an Apple account is required.
Requirements:
· 64-bit processor