Configuring Dreamweaver to detect the file compare application you have installed on Mac is very similar to Windows, with one major difference: Instead of pointing to the application file, you must select the command-line tool that launches the diff utility.
Click the Browse… button. On Mac, instead of browsing to the application file, Dreamweaver requires that you put it to a command-line utility that can invoke the file compare utility. In this case, browse to /usr/bin/opendiff, and click the Open button.
Figure 15. Browsing to and selecting the command-line utility that can invoke the file compare utility
A path to the opendiff command-line utility will display. Click OK to accept changes.
Figure 16. The File Compare preferences dialog box with the path to the the command-line utility that can invoke the file-compare utility