1. 修改my.cnf配置 sed -i ‘/mysqld/a\skip-grant-tables’ /etc/my.cnf 
2. 2
   重启mysql

   systemctl restart mysqld
3. 3
   进入mysql

   这次就不需要root密码了
4. 4
    use mysql;
5. 5
   UPDATE user SET Password = password('newpassword') where User = 'roo
6. 6
   刷新权限

   flush privileges; 
7. 7
   退出

   quit
8. 8
   还原my.cnf配置sed -i 's/skip-grant-tables/#skip-grant-tables/g' /etc/my.cnf
9. 9
   再次重启mysql服务

   systemctl restart mysqld

10.