Comparing Files the Easy Way: Apple's FileMerge

If you'd rather run FileMerge another way, then it will open with this dialog, in which you select the files to be compared using the Left... and Right... buttons. Which puts ist in the left view and ist in the right.

There are two official ways to open it: one is inside Xcode itself, from the Xcode menu, the other is, bizarrely, a command in Terminal, such as 'bbedit m1'. Installing a whole development environment just to get a tool to find differences might seem excessive, but there are many other good reasons to have Xcode and its tools to hand.

Apple used to deliver FileMerge and other Xcode support apps in a separate folder, but they're now buried away inside the Xcode.app folder, in Contents/Applications, so you'll probably want to install the app in your Dock, make an alias to it, or prepare some other means of ready access.

If you enjoy mixing sudoku with Scrabble, macOS comes with a full implementation of the standard Unix command diff. For us lesser mortals, there's a free app, FileMerge, which is bundled with Apple's Xcode SDK.

The first fact to note is that, if you're a command line wizard, you don't have to compare files the easy way. This article looks at Apple's free FileMerge tool for doing this, and more, and the Find Differences... feature in the Gold Standard text editor, BBEdit.

For many of us, similar comparisons need to be made even more often. Whenever Apple releases an update to XProtect's data files, I have to compare the new with the old to work out what has changed, for instance. Comparing two text files is one of those fundamental tasks which never seems to go away.

Bbedit m1