TkDiff File Comparison
graphical side by side "diff" utility
TkDiff is a graphical front-end for the standard Unix 'diff' utility.
Its features include highlighted difference regions (with a quick
overview/navigation bar) and linked scrolling of files. It provides
file-merge and change-summary facilities, line number toggling (for easier
cut & paste) and support for Subversion, RCS, CVS and SCCS.