mysql -u root fails with
Access denied for user 'root'@'localhost immediately after doing
brew install mariadb and starting mariadb with
brew services start mariadb.
To fix it (with MariaDB still running):
sudo mysql then enter your Mac user password
ALTER USER 'root'@'localhost' IDENTIFIED BY 'newrootpassword'; replacing
newrootpassword with the password you wish to use for the MariaDB root user.
- Ctrl-C to exit mysql.
You should then be able to connect to MariaDB with
mysql -u root -p, then entering the root password when prompted.