-- newuser.txt

CREATE USER newuser;
SELECT Host, User, Password FROM user;

+-----------------------+---------+----------+
| Host                  | User    | Password |
+-----------------------+---------+----------+
| localhost             | root    |          |
| localhost.localdomain | root    |          |
| localhost.localdomain |         |          |
| localhost             |         |          |
| %                     | newuser |          |
+-----------------------+---------+----------+

The new user is added with a default Host of "%", which is a wildcard for "any host".