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Licence: GPL 
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KDiff3 on Debian 

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Current version: 0.9.98 (2014-07-04)

Author: Joachim Eibl

Please write me your suggestions for KDiff3. (Tracker, Mailinglist)

KDiff3 is a diff and merge program that
  • compares or merges two or three text input files or directories,
  • shows the differences line by line and character by character (!),
  • provides an automatic merge-facility and
  • an integrated editor for comfortable solving of merge-conflicts,
  • supports Unicode, UTF-8 and other codecs, autodetection via byte-order-mark "BOM"
  • supports KIO on KDE (allows accessing ftp, sftp, fish, smb etc.),
  • Printing of differences,
  • Manual alignment of lines,
  • Automatic merging of version control history ($Log$),
  • and has an intuitive graphical user interface.
  • Windows-Explorer integration Diff-Ext-for-KDiff3 - shell extension included in installer (originally by Sergey Zorin: see also Diff Ext)
  • KDE-Konqueror/Dolphin service menu plugin
  • Simplified integration with IBM-Rational-Clearcase for Windows (Details).
  • Read what else is special in a short abstract (PDF).

Supported platforms:
  • KDE4
  • Any Un*x that is supported by the Qt-libs from qt-project.org,
  • MS-Windows.
  • Apple Mac OSX binary available. (0.9.98)
  • In theory any platform for which Qt-libs work (Qt4 or Qt5).

Translations by the KDE-I18N-Team:
  • Interface: az, bg, br, ca, cs, cy, da, de, el, en, en_GB, es, et, fr, ga, gl, hi, hu, is, it, ja, ka, lt, nb, nl, pl, pt, pt_BR, ro, ru, rw, sr, sr@Latn, sv, ta, tg, tr, uk, zh_CN
  • Documentation: en
  • Documentation (PDF): en, da, de, es, et, fr, it, nl, pt, sv,


Several precompiled packages are available, and if you are running Linux then your distribution might contain one. Yet if you want to build yourself then download the source package, unpack it via

tar xvfz filename.tar.gz

and follow the instructions in the README-file.


2014-07-04: Version 0.9.98
  • Text rendering now with QTextLayout fixes the following issues
    • Correct handling for variable width fonts.
    • Corrected display of highlighted text with Qt4.8.x on Ubuntu and Mac.
    • Improved handling of texts with both right to left and left to right languages (mixed Arabic and western texts).
    • Improved handling of Chinese and Japanese.
    • Whitespace characters are now shown as dots for spaces and arrows for tabs, and not only in differences.
  • Bugfixes.
For the complete list of changes and checksums see the Release Message
2013-02-14: Two Videos by myself (not exactly new, but previously unpublished)
2013-02-12: Video reviews
2012-08-12: Version 0.9.97
  • Memory usage optimized for comparison of large directories.
  • In overview for two way diff show if only one side contains text.
  • If text is selected in either input or output window use that in Find dialog.
  • Command line option --cs doesn't change the config value permanently anymore.
  • Windows 64 bit specific installer.
  • Bugfixes.
For the complete list of changes and checksums see the Release Message
2011-09-03: Version 0.9.96
  • KDiff3FileItemActionPlugin : Context menu that also works in Dolphin (for KDE>=4.6)
  • Detect encoding specified in xml header or html "meta" tag.
  • Warn if conversion errors appear (Invalid characters due to wrong encoding).
  • Translation update.
  • Bugfixes.
For the complete list of changes see the ChangeLog and the Release Message and MD5 sums.
2011-03-23: Blog by Marla Parker
A very nice user story about KDiff3.
2010-06-30: Binary package for OS2 created by Silvan Scherrer: kdiff3-0.9.95-os2ga.zip
If you are also interested in the Qt-port for OS2 and other ported applications, please see qt.netlabs.org, and svn.netlabs.org/qtapps.
2010-01-12: New package for Windows: KDiff3Setup_0.9.95-2.exe
Should fix the the explorer context menu extension on 64-bit systems.
2009-12-29: The integration into the explorer context menu doesn't yet work for 64-bit Windows.
Until I can fix this you might want to try Diff Ext by Sergey Zorin.
2009-03-25: Mac binary available for version 0.9.95 (created by Michael Schmidt)
2009-03-03: Version 0.9.95
  • Show line end style for each file.
  • Translation update.
  • Bugfixes.
For the complete list of changes see the ChangeLog and the Release Message and MD5-sums.
2009-01-17: Version 0.9.94
Bugfix release. For the complete list of changes see the ChangeLog and the Release Message.
2009-01-06: Version 0.9.93
  • KDE4 support (with much porting help from Valentin Rusu)
  • Build process uses cmake (instead of auto-tools like autoconf, automake etc.)
  • Dropped Qt3/KDE3 support (use 0.9.92 if you need this)
  • Optional auto detection of line end style for saving.
  • Option to close on ESC (default is off)
  • Option to align B and C for 3 input files (default is off which is usually better for merging).
  • Bugfixes.
For details see the Release Message.

2007-04-21: Newly compiled kdiff3-qt4.exe without dependencies in KDiff3Setup_0.9.92-2.exe.
2007-04-15: Version 0.9.92
  • Windows: Simplified Clearcase integration via installer and config dialogs.
  • KDE-Konqueror: Service menu plugin. (Use Konqueror to select files for comparison.)
  • The windows installer now also contains a Qt4-based executable for testing. It's launchable from the Start-menu. This will become the default soon.
  • Bugfixes.
2006-11-01: Version 0.9.91
  • Encoding auto detection for Unicode files with byte order mark "BOM" at the file start.
  • Diff-Ext-for-KDiff3 - shell extension for Windows included in installer (originally by Sergey Zorin: see also Diff Ext)
  • Fix for slow startup problem on Windows (Patch by Manfred Koehler)
  • Qt4-support: Much effort went into improving the KDiff3-Qt4-version and removing Qt3-support-dependencies but due to bugs in Qt4 it's still considered beta.
  • Qt4-sources: Now also contained in the same source package, subdir src-QT4.
  • Documentation and translations updated.
  • Bugfixes.
2006-09-18: Very positive review of KDiff3 by Brian Burridge
2006-05-14: Version 0.9.90 is a bugfix release
2006-04-09: Version 0.9.89 has a many big new features
  • Version control history auto merge plus sorting
  • Auto merge regular expression
  • Splitting and joining differences for merging
  • Manual Diff Alignment tool
  • Printing of differences
  • Colorsettings for Dir-Colors
  • Dir-show identical/different/A-only/B-only/C-only files with immediate effect (instead of option "List only deltas")
  • Filename-edit above DiffInputWindows
  • Windows-Context Menu in A/B/C-columns for dir-comparison (Windows only)
  • Edit Menu: Select All (Ctrl-A)
  • New commandline options:
  • --config filename: Select an individual config file. (Now also available for Windows and Qt-only version.)
  • --cs config: Change one specific setting via the command line. (For settings that were previously adjustable via GUI only.)
  • --confighelp: Show available config items and their current values.
  • Dircomp: "Compare/Merge explicitly selected files" (Select files/dirs by clicking icons in columns A/B/C)
  • User definable ignored command line options.
  • Ability to swap pathnames in open dialog
  • Bugfixes.
  • Documentation and translations updated.
See also the more detailed announcement on the mailing list.
2005-11-20: Filemanager contextmenus
Very useful: Info about filemanager contextmenus.

2005-03-06: Binary for Max-OSX
Mark Teel provided a binary of KDiff3-0.9.88 for the Apple Mac-OSX for download. (Linked statically against Qt, which means that it should just work.)

2005-02-25: Version 0.9.88
  • Bugfixes.
  • Translations updated.
2005-01-30: Version 0.9.87 - Finally Unicode Support!
  • Unicode16 and UTF8 support! (This was really tough. I hope you'll find it worth the long wait.)
  • Directory "Full Analysis": Equality-Coloring for files with only whitespace differences. (Michael Denio)
  • Support for right to left languages.
2004-06-14: Version 0.9.86 (Second version on same day!)

2004-06-14: Oops. Version 0.9.85 contains a very inconvenient regression. I'll fix it soon. Use 0.9.84 instead please.

2004-06-14: Version 0.9.85
Several Bugfixes

2004-05-31: Fixed Windows-DLL-dependency issue in KDiff3Setup_0.9.84-2.exe

2004-05-30: Version 0.9.84
New Features:
  • Word Wrap for DiffTextWindow
  • Directory-Comparison: Option "Full Analysis" allows to show the number of solved vs. unsolved conflicts or deltas vs. whitespace-changes in the directory tree.
  • Should now also work on 64-bit systems.
  • Docs now contain a new chapter for uses of preprocessor and line-matching-preprocessor.
  • Added several credits which now are also visible in the Qt-only version.
  • The Qt-only version now also shows all command-line options. Under windows a dialog shows them.
  • Command line options -u and -L for Subversion-support.
  • Command line options --L1/2/3 for specifying alias names.
  • In the Qt-only-version the user-interface-language can be set via the regional-settings (only effective after a restart).
  • Overview now allows to show the delta between two other files in triplediff-mode.
  • Option to ignore case which treats case-changes like white space (instead of conversion to upcase).

2004-03-06: Version 0.9.83
  • Reading directorys fixed for Win95/98/ME
  • Caseinsensitive filename matching for windows.
  • Autocopy to selection for systems that support this. (Patch by Stefan Partheymueller)
  • Windows: Start with invalid cmd-line-options brings up a messagebox with the list of options.
  • Corrected encoding when copying to or pasting from clipboard.
  • Warning when merging with preprocessor or upcase-conversion.
  • Rewrite of preprocessing code should fix several problems. E.g.:
  •     - Ignore C/C++-comments only worked with a preprocessor active.
  •     - Preprocessor output now is input of line-matching preprocessor.
  •     - Paste to diff-window, didn't work if LMPP or Ignore C/C++-Comments was set.
  • New interface languages by the KDE-I18N-Team: fr, ta

2004-02-19: I'm very happy to say that this project received its very first donation. Yippieh! See Donations.

Mailinglist kdiff3-user for questions, support and discussions available now.

2004-02-02: Version 0.9.82
  • DirectoryMerge: Running merge op for last item in a folder performed the merge op for all following items in following folders. (Possible data loss!)
  • Icon for "Highlight white space differences."
  • Editor-Option: Line End Style for saving: Dos/Windows "\r\n" vs. Unix "\n"
  • Speedup for reading directories under Windows.
  • New translations by the KDE-I18N-Team:
  •    - New interface language: ru
  •    - Documentation translations: da, et, it, sv

2004-01-08: Version 0.9.81
First steps towards internationalisation. Translations for message strings by the KDE-I18N-Team. Languages: da, de, es, et, hu, it, pt_BR, pt, sr, sv

2003-12-19: Abstract (pdf) added. Short information about what's special about KDiff3.

Older versions: (see Changelog in the package for details.)