In iOS 7, Apple quietly added new keyboard shortcuts to some of its apps and gave developers the capability to add their own. So if you use a Bluetooth keyboard with your iOS 7 device, be sure to bookmark this list of shortcuts that Federico Viticci is working on. Since there is no official documentation from Apple, Viticci is learning them by trial and error, as well as from reader submissions, and he will update the list as he learns more. follow link
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New Keyboard Shortcuts in iOS 7