Binary diff and patch programs for the Windows command line
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BDiff / BPatch

Binary diff and patch programs for the Windows command line.


BDiff computes differences between two binary files. Output can be either a somewhat human-readable protocol in plain text, or a binary file that is readable by BPatch.

BPatch applies a binary patch generated by BDiff to a file to recreate the original file.

See the files BDiff.txt and BPatch.txt in the Docs directory for details of how to use the programs.

BDiff and BPatch are derived from Stefan Reuther's bdiff and bpatch v0.2 and a later bug fix by Stefan.

The original C source was translated into Object Pascal by Peter D Johnson (@delphdabbler). The programs are are based on updates of the Pascal code base.

The programs should run on any current version of Windows.

For more information see the see the project web pages.


Copy the provided executable files to the required location. No further installation is required.

You may want to modify the Windows PATH environment variable to include the location of the programs.

To uninstall simply delete the programs. They make no changes to the system. If you changed the PATH environment variable you may wish to adjust this.


You can test the operation of BDiff and BPatch using the Test.bat script in the Test directory. See ReadMe.txt in that directory for details.

Source Code

Pascal Source

The current source code is maintained in the delphidabbler/bdiff Git repository on GitHub. It contains releases going back to v0.2.5. Earlier versions were not under version control and are no longer available.

Note: Until February 2014 the source code was maintained in a Subversion repository. A dump of the repo is available from Google Drive.

For information on how to build the Pascal source, see Build.txt in the root of the Git repo.

C Source

The original C source code can be downloaded from

Copyright and License

See the file for details of copyright and the license that applies to this software.

Change Log

The change log is provided in the file CHANGELOG.txt.