Compare Two Files with FileMerge in Mac OS X
If you’re a developer and you haven’t found out about FileMerge yet, you are missing out on one of the more useful apps included within Apple’s XCode installation. FileMerge lets you select any two files and it will compare the two, pointing out any differences between the files. If you’re a developer you already know why this is wildly useful, as it makes tracking down major and minor code changes remarkably easy. Apparently FileMerge is a survivor from the days of NeXTStep, and once you see how useful it is, you’ll see why it was saved and bundled with XCode.
To get FileMerge for free, you’ll need Xcode, which can be installed from the App Store, one of the disks included with your Mac (if yours came with one), or downloaded for free from the Apple Developer site. Once XCode has been installed, FileMerge will be located at /Developer/Applications/Utilities/FileMerge at the root of your OS X installation.
Just launch the application, select your two files to compare (and merge, if you want to do that), and see how awesome it works.
Of course, this is intended for more advanced comparisons and merging and aimed primarily at developers comparing code versions. More average use for comparing say, two generic text documents, can be done with FileMerge as well, but an easier option that is more friendly to most users would be to use an app like Microsoft Word to compare two DOC text files.
The above FileMerge screenshot comes from Schwehr.org.