Tkdiff

tkdiff is a graphical diff viewer based on the Tk framework. It is capable of inter-operating with source-control systems like CVS and Subversion to show the differences between the local copy and the repository version. Such a line-by-line comparison is often considered to be good software engineering practice before committing code changes.

Tkdiff distinguishes itself from many alternatives by highlighting specific differences within a line shared by both files, rather than simply indicating that the whole line differs.