https://www.linuxidc.com/Linux/2017-04/143209.htm liunx安装
https://www.jb51.net/article/97905.htm
https://www.cnblogs.com/xinjie10001/p/6295020.html 切换用户
https://jingyan.baidu.com/article/c843ea0ba8b70677931e4adc.html lynx网关配置
rpm -qa | grep -i mysql 是否安装mysql
rpm -ev mysql-community-libs-5.6.40-2.el7.x86_64 卸载
