1，此源代码为本人所写，非ＧＮＵ的源代码，不要因此而唔到大家，摆出此来仅供交流

２，此源代码不完整，ｓｈｅｌｌ的很多功能都没有实现，知识实现了一些主要的功能

3，实现功能如下：

a，输入命令，并运行

b，实现if 和while的深层嵌套

c，实现环境变量，和shell本身变量

d，实现管道和重定向等功能。

4，由于能力问题，程序可能有错误，欢迎高手指点。-1, this source code I wrote, non-GNU source code, do not be not able to meet everyone that put this to the exchange of only two, this source code is not complete, shell functions are not achieved a lot of knowledge to achieve a number of The main function of three to achieve the following functions: a, enter the command, and run the b, to achieve if, and while the deep nested c, achieving environmental variables, and the shell itself, the variable d, to achieve piping and redirection functions. 4, due to capacity problems, the program may be an error, please master pointing.