http://blog.csdn.net/buutterfly/article/details/6615162
http://www.2cto.com/os/201307/224496.html
http://wenda.so.com/q/1365651781067621
http://www.cnblogs.com/luwikes/archive/2011/09/14/2176581.html
grep
http://blog.sina.com.cn/s/blog_406127500101dljv.html
awk:
http://www.linuxidc.com/Linux/2013-07/87047.htm
http://www.cnblogs.com/chengmo/archive/2010/10/08/1845913.html
mount:
http://www.cnblogs.com/chengmo/archive/2010/10/13/1850515.html
