Instead of resetting the password there is a work around on the local machine if you have setup phpmyadmin to connect without giving the password or username. Check this out by starting mysql, apache etc. I have xampp installed in my local machine. So starting the xampp will start all the necessary services. Now going to http://localhost/phpmyadmin shows me all the databases. This confirms that you have saved the username and passsword in the config file of phpmyadmin which can be found in the phpmyadmin install location. If you have xampp installed the phpmyadmin folder can be found in the root folder of xampp installation. Search for the word password in the config.inc.php file. There you will find the password and username.

设置MySQL密码

停止MySQL数据库服务

sudo /etc/init.d/mysql stop

创建一个新的mysqld目录

Sudo mkdir /var/run/mysqld/

给予mysql用户访问权限

Sudo chown mysql /var/run/mysqld/

以安全模式启动MySQL…

Sudo mysqld_safe—skip-grant-tables &

无需密码登录数据库服务器

Sudo mysql -u root

使用默认的mysql数据库

使用mysql;

修改root密码

update user set authentication_string=PASSWORD(" new_passwor_here ") where user ='root';

保存更改 冲洗特权; 退出; 停止MySQL安全模式，启动MySQL默认服务

sudo /etc/init.d/mysql stop

sudo /etc/init.d/mysql start

使用root新密码重新登录MySQL数据库

-u root -p

***来源:https://websiteforstudents.com/resetting-mysql-root-password-on-ubuntu-16-04-17-10-and-18-04-lts/

对我有用的(Ubuntu 16.04, mysql 5.7):

停止MySQL

sudo service mysql stop

制作MySQL服务目录。

sudo mkdir /var/run/mysqld

赋予MySQL用户写入服务目录的权限。

sudo chown mysql: /var/run/mysqld

手动启动MySQL，不需要权限检查或联网。

sudo mysqld_safe --skip-grant-tables --skip-networking &

在另一个控制台，无需密码登录。

mysql -uroot mysql

然后:

UPDATE mysql.user SET authentication_string=PASSWORD('YOURNEWPASSWORD'), plugin='mysql_native_password' WHERE User='root' AND Host='localhost';
EXIT;

关闭MySQL。

sudo mysqladmin -S /var/run/mysqld/mysqld.sock shutdown

正常启动MySQL服务。

sudo service mysql start

重置或修改密码请输入sudo dpkg-reconfigure mysql-server-X。X (X.X是mysql版本你已经安装，即5.6,5.7)，然后你会提示一个屏幕，你必须设置新密码，然后在下一步确认密码，只是等待一会儿。就是这样。

该任务指导用户在Ubuntu操作系统下设置/修改/重置MySQL root密码。在终端中输入以下行。

停止MySQL服务器:sudo /etc/init.d / mysql停止 (在某些情况下，如果/var/run/mysqld不存在，你必须首先创建它:sudo mkdir -v /var/run/mysqld && sudo chown mysql /var/run/mysqld 启动mysqld配置:sudo mysqld——skip-grant-tables & 以root身份登录MySQL: MySQL -u root MySQL 用你的新密码替换YOURNEWPASSWORD:

MySQL < 8.0

UPDATE mysql.user SET Password = PASSWORD('YOURNEWPASSWORD') WHERE User = 'root';
FLUSH PRIVILEGES;

如果你的MySQL使用新的认证插件，你将需要使用:update user set plugin="mysql_native_password" where user ='root';在冲洗特权之前。

注意:在某些版本，如果密码列不存在，你可能想尝试: UPDATE user SET authentication_string=password('YOURNEWPASSWORD') WHERE user='root';

注意:这种方法不是最安全的重置密码的方法，但它是有效的。

对于MySQL >= 8.0

FLUSH PRIVILEGES;
ALTER USER 'root'@'localhost' IDENTIFIED BY 'YOURNEWPASSWORD';
FLUSH PRIVILEGES;

最后一步:

正如@lambart的评论中所提到的，你可能需要杀死你启动的临时无密码mysql进程，即sudo killall -9 mysqld，然后启动正常的守护进程:sudo service mysql start

引用:

该任务指导用户在Ubuntu Linux下设置/修改/重置MySQL root密码 如何重置Root用户密码(v5.6) 如何重置Root用户密码(v8.0)

I had to go this route on Ubuntu 16.04.1 LTS. It is somewhat of a mix of some of the other answers above - but none of them helped. I spent an hour or more trying all other suggestions from MySql website to everything on SO, I finally got it working with: Note: while it showed Enter password for user root, I didnt have the original password so I just entered the same password to be used as the new password. Note: there was no /var/log/mysqld.log only /var/log/mysql/error.log Also note this did not work for me: sudo dpkg-reconfigure mysql-server-5.7 Nor did: sudo dpkg-reconfigure --force mysql-server-5.5 Make MySQL service directory. sudo mkdir /var/run/mysqld Give MySQL user permission to write to the service directory. sudo chown mysql: /var/run/mysqld Then:

kill the current mysqld pid run mysqld with sudo /usr/sbin/mysqld & run /usr/bin/mysql_secure_installation Output from mysql_secure_installation root@myServer:~# /usr/bin/mysql_secure_installation Securing the MySQL server deployment. Enter password for user root: VALIDATE PASSWORD PLUGIN can be used to test passwords and improve security. It checks the strength of password and allows the users to set only those passwords which are secure enough. Would you like to setup VALIDATE PASSWORD plugin? Press y|Y for Yes, any other key for No: no Using existing password for root. Change the password for root ? ((Press y|Y for Yes, any other key for No) : y New password: Re-enter new password: By default, a MySQL installation has an anonymous user, allowing anyone to log into MySQL without having to have a user account created for them. This is intended only for testing, and to make the installation go a bit smoother. You should remove them before moving into a production environment. Remove anonymous users? (Press y|Y for Yes, any other key for No) : y Success. Normally, root should only be allowed to connect from 'localhost'. This ensures that someone cannot guess at the root password from the network. Disallow root login remotely? (Press y|Y for Yes, any other key for No) : y Success. By default, MySQL comes with a database named 'test' that anyone can access. This is also intended only for testing, and should be removed before moving into a production environment. Remove test database and access to it? (Press y|Y for Yes, any other key for No) : y Dropping test database... Success. Removing privileges on test database... Success. Reloading the privilege tables will ensure that all changes made so far will take effect immediately. Reload privilege tables now? (Press y|Y for Yes, any other key for No) : y Success. All done!