How to set Mac OS X to portrait mode

Rotating the screen on Mac OS is quick and simple:

1. Launch the System Preferences from the Apple  menu.
2. Hold down the Cmd+Alt keys and click on the “Displays” icon.
3. On the right side of the Display preferences, look for the newly visible ‘Rotation’
   drop down menu.
4. Set to the rotation you want. In this case, you probably want to rotate 90° for the display to go into a vertical page layout orientation.
5. Close out the System Preferences to have the settings go into effect.