mysql怎么查看用户名？

[root@server ~]# mysqld_safe &[1] 3289
[root@server ~]# 130913 08:19:58 mysqld_safe Logging to '/usr/local/mysql/data/server.gao.err'.
130913 08:19:58 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/data

[root@server ~]# mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.6.13 MySQL Community Server (GPL)

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>

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
+--------------------+
rows in set (0.00 sec)

mysql>

mysql> use mysql;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> select host,user from mysql.user;
+------------+------+
| host       | user |
+------------+------+
| 127.0.0.1  | root |
| ::1        | root |
| localhost  |      |
| localhost  | root |
| server.gao |      |
| server.gao | root |
+------------+------+
rows in set (0.00 sec)

mysql>