mysql set root password

use mysql;

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

flush privileges;

quit

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

$ sudo apt install mysql-server
$ sudo cat /etc/mysql/debian.cnf

ALTER USER 'root'@'localhost' IDENTIFIED WITH caching_sha2_password BY 'yourpasswd';
exit;