解决方法
对于Mac：
gem install rb-appscript
然后你可以用这样的脚本测试它：
require "rubygems"
require "appscript"
include Appscript
app("TextEdit").activate
app("System Events").keystroke("Look Ma,keystrokes!")
对于Windows :(未经测试,borrowed from this thread)
require "win32ole"
wsh = WIN32OLE.new("WScript.Shell")
wsh.Run("Notepad.exe")
while not wsh.AppActivate("Notepad")
sleep .1
end
wsh.SendKeys("Look Ma,keystrokes!")