1.正则表达式
http://www.runoob.com/regexp/regexp-metachar.html
2.python正则表达死
http://www.runoob.com/python/python-reg-expressions.html#flags
3.python内置函数
http://www.runoob.com/python/python-built-in-functions.html
4.linux教程
http://www.runoob.com/linux/linux-comm-pwd.html