了解常用shell的编程特点，掌握shell程序设计的基础知识。对shell程序流程控制、shell程序运行方式、bash程序的调试方法及bash的常用内部命令又进一步的认识和理解。通过本实验，应基本掌握编写shell程序的步骤、方法和技巧-Understand the common features of shell programming, shell programming to master the basic knowledge. Shell procedures for flow control, shell program to run mode, bash debugging methods and procedures commonly used bash internal command further awareness and understanding. Through this experiment, should be prepared to master the basic shell procedure, methods and techniques