change user mysql
snippet in sql

mysql deltete user

user4256

DROP USER 'jeffrey'@'localhost';

change user mysql

user915

[madegow@fedora20 ~]$ mysql -u root -p
Enter password: 
...
MariaDB [(none)]> select user()
-> ;
+----------------+
| user()         |
+----------------+
| root@localhost |
+----------------+
1 row in set (0.00 sec)

MariaDB [(none)]> system mysql -u madegow -p
Enter password: 
...
MariaDB [(none)]> select user();
+-------------------+
| user()            |
+-------------------+
| madegow@localhost|