shell getopts 用法

http://www.cnblogs.com/xupeizhi/archive/2013/02/18/2915659.html

http://blog.csdn.net/xluren/article/details/17489667

http://my.oschina.net/HankCN/blog/116120

基本使用

http://learn.tsinghua.edu.cn/kejian/data/77130/138627/html-chunk/ch31s02.html