Applescript to reset all iOS Simulators' Contents & Settings
In Mavericks, you must go to your Security & Privacy preference pane in System Preferences. From there, select the Privacy tab and then Accessibility. Enable AppleScript Editor under "Allow the apps below to control your computer."
Option 1: The "Reset All Simulators.scpt" script can be run standalone by opening with Applescript and pressing the Run button.
Option 2: The script can be run from the command line with: osascript Reset\ All\ Simulators.scpt
Option 3: The script can be referenced from or copy/pasted into an Xcode Run Script. Make sure to set the Shell to /usr/bin/osascript