File comparison and merge tool;
EditByBSEditor: xxdiff is provided under the GNU GPL open source license. It has reached stable state, and is known to run on many popular unices, including IRIX, Linux, Solaris, HP/UX, DEC Tru64. It has been deployed inside many large organizations and is being actively maintained by its author (Martin Blais).
Features

* Comparing two files, three files, or two directories (shallow and recursive);
* Horizontal diffs highlighting;
* Files can be merged interactively and resulting output visualized and saved;
* Has features to assist in performing merge reviews/policing;
* Can unmerge CVS conflicts in automatically merged file and display them as two files, to help resolve conflicts;
* Uses external diff program to compute differences: works with GNU diff, SGI diff and ClearCases cleardiff, and any other diff whose output is Similar to those;
* Fully customizable with a resource file;
* Look-and-feel similar to Rudy Wortels/SGI xdiff, it is desktop agnostic (i.e. will work equally well with KDE or GNOME);
* Features and output that ease integration with scripts.

xxdiff was (and probably still is) tested daily in a merge reviewing/policing context by more than 50 engineers at discreet, and since this task is a significant part of their development process, many of the features are a direct result of suggestions from these people while the author was working there. you can free download xxdiff for linux 3.2 now.