MySQL: How to reset or change the MySQL root password?

Set / change / reset the MySQL root password on Ubuntu Linux. Enter the following lines in your terminal.

1. Stop the MySQL Server: sudo /etc/init.d/mysql stop
2. Start the mysqld configuration: sudo mysqld --skip-grant-tables &

In some cases, you’ve to create the /var/run/mysqld first:

    sudo mkdir -v /var/run/mysqld && sudo chown mysql /var/run/mysqld

3. Login to MySQL as root: mysql -u root mysql
4. Replace YOURNEWPASSWORD with your new password:

For MySQL < 8.0

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

Note: on some versions, if password column doesn’t exist, you may want to try:
UPDATE user SET authentication_string=password('YOURNEWPASSWORD') WHERE user='root';

Note: This method is not regarded as the most secure way of resetting the password, however, it works.

For MySQL >= 8.0

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

References:

1. Set / Change / Reset the MySQL root password on Ubuntu Linux
2. How to Reset the Root Password (v5.6)
3. How to Reset the Root Password (v8.0)