Ubuntu: MySQL: ERROR 1698 (28000): Access denied for user 'root'@'localhost'


$ mysql -u root -p
Enter password: 
ERROR 1698 (28000): Access denied for user 'root'@'localhost'


$ sudo mysql -u root

Database changed
mysql> SELECT User, Host, plugin FROM mysql.user;
+------------------+-----------+-----------------------+
| User             | Host      | plugin                |
+------------------+-----------+-----------------------+
| root             | localhost | auth_socket           |


Update