Send random arrow keys using ruby, Mac OS X only

gistfile1.rb

#!/usr/bin/ruby -w

def presskey(keycode)
  system "osascript -e 'tell application \"System Events\" to key code #{keycode}'" 
end

kVK_LeftArrow    = 123     
kVK_RightArrow   = 124
kVK_DownArrow    = 125
kVK_UpArrow      = 126     
arrow_keys = [kVK_LeftArrow, kVK_RightArrow, kVK_DownArrow, kVK_UpArrow]

if $0 == __FILE__
  sleep(2)
  while(true) do
    presskey(arrow_keys.sample)
    sleep(0.4)
  end
end

Another example (this one is multiline):

system "osascript -e 'tell application \"System Events\"' -e 'keystroke \"t\" using control down' -e 'end tell'"