一个简单的命令解释器—模拟shell 功能的程序，实现要求中所提到的可打开提示符，并获取用户输入的指令、可解析指令、可寻找命令文件、可执行基本的命令等功能-A simple command interpreter- simulated shell function procedures, to achieve the requirements mentioned in the prompt to open and obtain user input commands can resolve directive order to find documents, executable command basic functions