检測本机是否有安装mysql
sudo netstat -tap | grep mysql运行上面的命令之后。看到 mysq 的socket 处于监听状态，说明有成功安装。
安装mysql
sudo apt-get install mysql-server mysql-client libmysqlclient-dev安装过程中会提示输入数据库管理员密码（自己设定的），如图
设置完毕之后等待安装完毕就可以。
mysql 的登陆与退出
$ mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or g.
Your MySQL connection id is 45
Server version: 5.5.43-0ubuntu0.12.04.1 (Ubuntu)
Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
mysql> quit;
Bye