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Finally, a real Mac graphical "differ" that is
suitable for use from the command line
(Or from your remote Unix system.)

Fun Features

• Additions, deletions, and changes to the file are shown in different colors.
• The vertical scrollbar provides a "heads-up" preview of the differences, making easy to spot the magnitude and the density of the differences.
• A handy "Differences" menu enables quick jumping to any change.
• At the bottom of the screen, a horiztonal comparison view is provided that assists in visualizing subtle changes to individual lines.

RoaringDiff is...

1. A native Mac OS X application (Universal Binary for PowerPC and Intel).
2. Controllable from the command line and suitable for p4 diff or svn diff operations from the Terminal.
3. A 1.0 release, which means missing "obvious" features and some bugs. :-)
4. Not a "diff3" replacement.
5. Not a merge tool.

RoaringDiff provides friendly file comparison for programmers, web developers, or anyone else responsible for frequently changing text files such as source code, web pages, or XML data.

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Using with 'svn' command line

You can point svn to RoaringDiff manually every time you run svn diff:

$ svn diff --diff-cmd /Applications/RoaringDiff.app/Contents/MacOS/RoaringDiff

This becomes tedious quickly. If you plan to use RoaringDiff for most of your diffing, edit ~/.subversion/config and change diff-cmd in that file:

### Set diff-cmd to the absolute path of your 'diff' program.
###   This will override the compile-time default, which is to use
###   Subversion's internal diff implementation.
# diff-cmd = diff_program (diff, gdiff, etc.)
diff-cmd = /Applications/RoaringDiff.app/Contents/MacOS/RoaringDiff

To use the regular GNU diff from time to time when diff-cmd is set, you can run:

$ svn diff --diff-cmd diff

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Using with 'p4' command line

For use with Perforce, just set P4DIFF to the RoaringDiff executable. You can do this in your shell configuration (~/.profile for bash users).

export P4DIFF=/Applications/RoaringDiff.app/Contents/MacOS/RoaringDiff

To use the regular GNU diff from time to time when P4DIFF is set, bash users can run:

$ P4DIFF=diff p4 diff

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Known Bugs/RFEs

• Port QuickDraw rendering code to Quartz (150).
• Closing the diff window should quit the app if the app was started from the command line (152).
• Extremely large files suffer from poor performance and possibly other problems (149).
• Reversing the diff direction does not update the "Differences" menu (145).
• Add X11-style geometry flags to the command line options to control what screen(s) to show the window on, and the dimensions of the window (147).
• The pop-up menu list of recently viewed files will include temporary files from p4 or svn; these should be removed or flagged as missing from the filesystem (154).
• Remove the dependency on GNU diff (156).
• The maximum line width is 262,144 characters (155).
• There are some minor issues with disabling diff features (e.g., do not compare whitespace) and the rendering of the right file. The right file is rendered as a set of changes to the left, so if changes are ignored, they are not shown on the right (157).

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Feedback

I mostly wrote RoaringDiff because it is a tool that I want to use. If you find it useful, I'd love to hear how you're using it. My main pet peeve was the lack of a GUI differ than has "proper" command-line control for using with Perforce and Subversion.

I wanted something like xxdiff on the Mac (but xxdiff has some strangeness that bugs me, too). opendiff(1) drives me crazy--I want "synchronous diffing" and control over the colors and geometry.

Send me mail: mitch.haile@gmail.com.

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Copyright © 2006-2008 by Mitch Haile. All rights reserved.