How to get overview of keyboard shortcuts from OS X? I would like to know about keyboard shortcuts, that is, shortcuts that are mentioned nowhere in the menus, nor anywhere, and must be found by stumbling upon them in sites like these, but still work.

Examples:


⌘⇧., which shows or hides hidden files in a save or open dialog box.
⌘⌥⏏, which causes the computer to go to sleep.
⌘⌥⇧⌃., which runs sysdiagnose and shows the results in the finder.


Does anyone know of more of these or how I can get an overview of these shortcuts?
I find the free app CheatSheet is a great way to show what shortcuts are available, Install it and it runs in the background, then just hold the ⌘ key down for a couple of seconds without choosing an operand to get a list of all active short cuts of the current application.



CheatSheet uses the Accessibility API to read the menus of the current application, but you need to turn on support for Assistive Devices to allow this - the app shows instructions how to do it.  Because of this, it can only show the shortcuts that are obvious, and it might not show shortcuts that are not displayed via your apps menu bars, but nevertheless it's a brilliant way to learn an apps common shortcuts - once y ou have held down the key to show the list, you can then continue to type in the shortcut you want, so it doesn't need any new workflow to use it effectively, just a pause if you are not sure what you want to use.