[MariaDB] ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

EC2

mysql -uroot

failed with error 2002

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

-> in my case mariadb service was inactivated because I stopped and restart the instance
-> so I ran commands

systemctl enable mariadb
systemctl start mariadb