How to change the mysql root password

One option is to save UPDATE mysql.user SET Password=PASSWORD('newpass') WHERE User='root'; into a file and then manually start mysqld with --init-file=FILENAME. Once the server starts, it should reset your password, and then you should be able to log in. After this, you should shut down the server and start it normally.

A little late to the game, but I had the same issue on a raspberry pi install and found out that it needs elevation. Adding a sudo to the front of the password change allowed it to work.

sudo mysqladmin -u root password 'newpass'

followed by an elevated sql access

sudo mysql -u root -p  

If either are not run as sudo, it will fail.

The root user password is an empty string by default.

And (using password: NO) says that there is no password.

Do you try to login from another system? I imagine you can only login as root user locally.