mysql -u root

mysql -u root -p

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

mysql -u root

ERROR 2002 (HY000): Can't connect to local MySQL server through socket
'/var/run/mysqld/mysqld.sock' (2)

sudo apt-get --purge remove mysql-server mysql-common mysql-client

sudo apt-get install mysql-server mysql-common mysql-client

mysqladmin -u root password my-new-password

mysqladmin: connect to server at 'localhost' failed
error: 'Access denied for user 'root'@'localhost''

sudo mysql -u root