linux下更改mysql的root密码

2．修改MySQL的登录设置：
vim /etc/my.cnf
在[mysqld]的段中加上一句：skip-grant-tables
例如：
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
skip-grant-tables
保存并且退出vi。

3．重新启动mysqld
service mysqld restart
Stopping MySQL: [ OK ]
Starting MySQL: [ OK ]
或者出现：
Redirecting to /bin/systemctl restart mysqld.service

4．登录并修改MySQL的root密码
mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3 to server version: 3.23.56
Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the buffer.
mysql> USE mysql ;
Database changed
mysql> UPDATE user SET Password = password ( ‘123456’ ) WHERE User = ‘root’ ; （注意括号里单引号内的就是你要重新设置的密码）

所以应当修改的是authentication_string这一列

Query OK, 0 rows affected (0.00 sec)
Rows matched: 5 Changed: 0 Warnings: 0
mysql> flush privileges ;
Query OK, 0 rows affected (0.01 sec)
mysql> quit
Bye

5．将MySQL的登录设置修改回来
vim /etc/my.cnf
将刚才在[mysqld]的段中加上的skip-grant-tables删除
保存并且退出vim

6．重新启动mysqld
service mysqld restart
Stopping MySQL: [ OK ]
Starting MySQL: [ OK ]
或：
Redirecting to /bin/systemctl restart mysqld.service

7.检测新密码是否生效
输入mysql -u root -p 回车
然后输入新密码，回车，如下图修改成功