Login with root-privileges work with simply "mysql".
That is ok!
[root@www ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 307
Server version: 5.1.73 Source distribution
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> GRANT SELECT ON test.* TO 'admin'@'host' IDENTIFIED BY 'mypassword';
Query OK, 0 rows affected (0.00 sec)
mysql>