Keycodes and Modifier Values for Binding Hidden Commands

Modifier values

Each modifier has an integer value. Combinations are the sum.

Letter keys

Numbers, punctuation and special keys

Finding a key that is not listed

Function keys, numeric keypad keys and anything on a non-US layout are easiest to identify by pressing them in a utility that reports the code. Free keycode viewers exist on the App Store and are the approach the official documentation recommends.

Alternatively, bind the key you want through the settings window to any ordinary command, then read back what was stored:

# bind the key via the interface first, then:
defaults read com.knollsoft.Rectangle leftHalf

# output shows the keyCode and modifierFlags actually recorded
{
    keyCode = 123;
    modifierFlags = 786432;
}

This is the most reliable method, because it reports exactly what your keyboard layout produces rather than what a table says it should.

Putting it together

D=com.knollsoft.Rectangle

# ctrl+opt+shift+1 → top-left ninth
defaults write $D topLeftNinth -dict-add keyCode -float 18 modifierFlags -float 917504

# ctrl+opt+shift+right → double width rightward
defaults write $D doubleWidthRight -dict-add keyCode -float 124 modifierFlags -float 917504

# ctrl+opt+] and ctrl+opt+[ → width only, larger and smaller
defaults write $D largerWidth -dict-add keyCode -float 30 modifierFlags -float 786432
defaults write $D smallerWidth -dict-add keyCode -float 33 modifierFlags -float 786432

# ctrl+shift+1 → tile the frontmost app's windows
defaults write $D tileActiveApp -dict-add keyCode -float 18 modifierFlags -float 393216

killall Rectangle && open -a Rectangle

To remove a binding you added, delete the key entirely rather than writing an empty value:

defaults delete com.knollsoft.Rectangle topLeftNinth

Questions