Linux 命令在线手册
https://www.linuxcool.com
MySQL 四部曲
https://www.cnblogs.com/cxuanBlog/p/13173547.html 入门
https://www.cnblogs.com/cxuanBlog/p/13352975.html 进阶
https://www.cnblogs.com/cxuanBlog/p/14865500.html 优化
https://www.cnblogs.com/cxuanBlog/p/13352975.html 高阶
https://www.cnblogs.com/cxuanBlog/p/14291088.html DNS