View Firefox page source in an external editor - Mac OS X Hints

To do this, you need to enter about:config in Firefox's URL bar, then accept the warning when prompted. In the Filter box, type source.editor, which will show you three variables. Double-click on view_source.editor.external first, to change its Value to true. Next, double-click on view_source.editor.path, which will drop down a small sheet in which you enter the path to your preferred editor. The path must be a full complete Unix-style path, and point to the actual executable (not the app bundle). So for Coda, I used: