这时一个模拟用户运行的程序，它可以在一个用户空间模拟另一个用户运行任意的外部程序。-Then a simulated user procedures, It can be a user space simulation another user to run arbitrary external programs.

RunAs工具，实现以任意用户身份运行程序。可以以管理员、系统、普通用户身份运行任意程序。-RunAs tool in order to achieve any user run the program. Can the administrator, system, regular user to run any program.