MARIADB

Alterando senha root

systemctl stop mysqld ou systemctl stop mariadb

mysql_safe --skip-grant-tables &

mysql -u root

mysql> use mysql;  
 mysql> update user set password=PASSWORD("NOVA SENHA DO ROOT") where User='root';  
 mysql> flush privileges;

OPCIONAL - Redefinir as permissões

 mysql> grant all privileges on *.* to 'root'@'%';  
 mysql> grant all privileges on *.* to 'root'@'localhost';  
 mysql> grant all privileges on *.* to 'root@localhost';  

Finalizando:

 mysql> SHOW GRANTS FOR 'root'@'%';  
 mysql> FLUSH PRIVILEGES;  

systemctl start mysqld ou systemctl start mariadb