http://tinypig.javaeye.com/blog/422468
http://www.example-code.com/python/ssh.asp
http://pexpect.sourceforge.net/pxssh.html
http://bbs2.chinaunix.net/thread-1606045-1-1.html
http://www.koders.com/python/fidA430838E5789710E4DCF34C414AD75EB4EEE63CF.aspx
https://www.ibm.com/developerworks/cn/linux/l-cn-pexpect1/
http://bbs2.chinaunix.net/thread-1468942-1-9.html
http://old.nabble.com/-CPyUG:104442--python-ssh-%E6%A8%A1%E5%9D%97-td25968895.html