xxdiff: Graphical File And Directories Comparator And Merge Tool

Table of Contents


This is the official home of xxdiff, a graphical file and directories comparator and merge tool.

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).


  • 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 ClearCase's cleardiff, and any other diff whose output is similar to those;
  • Fully customizable with a resource file;
  • Look-and-feel similar to Rudy Wortel's/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.

Unicode and Inline Editing

xxdiff does not support comparing files encoded with Unicode. Also, it does not support inline editing of the diffed files. If you need these features, you could try emacs or Meld (although both of these lack some of the most interesting features of xxdiff).




xxdiff comes with a bunch of wrapper Python scripts that invoke xxdiff in creative ways. The author has been using these for a long time now and decided for version 3.0 to clean them up and make them a little more generic so everyone can use them. As of version 3.2, the standalone scripts have been refactored a great deal, to share code together and to make them more stable. All this code is now distributed with xxdiff, in an xxdiff Python package, which you can leverage to build your own file transformation scripts around xxdiff.

See the document Helper Scripts for xxdiff for full details.

The scripts are available in the xxdiff distribution. To install them and the accompanying Python package, use the standard distutils procedure:

su -  # before root
cd xxdiff-3.x
python setup.py install

Other tools can be found in the distribution under the tools/ directory (CVS, ClearCase, etc.).


Packages are available for some specific operating systems. Here are links to the relevant pages. The author does not publish binaries anymore.

Reporting Bugs



Build dependencies are:

  • Qt-4.5 or higher
  • a C++ compiler, flex and yacc

Runtime dependencies are:

  • Qt-4.5 or higher


xxdiff is known to build and work on a great majority of UNIX platforms where Qt works, including Mac OS X.


Martin Blais <blais@furius.ca>