Function key setting on Mac - secure411dotorg/mal4s GitHub Wiki

By default your Mac may be set up for the F1 through F12 keys to do other things such as setting the brightness of your display. If you stick with the default mode you can get F5 F7 and F9 functionality by holding the Fn key down while pressing the key. If you tire of this, set your function keys to your liking this way:

http://support.apple.com/kb/HT3399?viewlocale=en_US&locale=en_US