Today I found myself locked out of MySQL because in the new server setup I managed to lose the password. Fortunately, there is a relatively straightforward way to reset it.
First, check the current version number of the MySQL being used.
apt-cache policy mysql-serverThen, type in the command below where *.* refers to version number.
sudo dpkg-reconfigure mysql-server-*.*Voilà, now you can login with the new credentials!
mysql -u root -p