How do I know what to put in DefaultKeyBinding.dict?
There is a wonderful resource on DefaultKeyBinding.dict including an example file as well as all the shortcut strings and methods you need, available at:


https://github.com/ttscoff/KeyBindings


There are also numerous other resources listed at the bottom of the page, including the official Apple Developer documentation:


https://developer.apple.com/library/mac/documentation/cocoa/conceptual/eventoverview/TextDefaultsBindings/TextDefaultsBindings.html