关于正则表达式，sed与awk命令的参考
http://www.linuxsir.org/bbs/showthread.php?t=198391
http://linux.chinaunix.net/techdoc/develop/2007/02/10/950229.shtml
http://bbs.chinaunix.net/thread-1389781-1-1.html
http://bbs.tsinghua.edu.cn/pc/pccon.php?id=2207&nid=82422&tid=7624
http://baike.baidu.com/view/94238.htm?fr=ala0_1
http://vvnet.iteye.com/blog/449974
