cat /etc/issue
http://www.jianshu.com/p/0cf2c57bd61b
https://mariadb.com/kb/en/mariadb/yum/
中文版：https://mariadb.com/kb/zh-cn/installing-mariadb-with-yum/
常用linux命令
原文：http://www.cnblogs.com/jeacy/p/7182774.html
