How to display all MySQL server system variables and the values?

# mysqladmin  -u root -p******** variables
+---------------------------------+---------------------------------+
| Variable_name                   | Value                           |
+---------------------------------+---------------------------------+
| auto_increment_increment        | 1                               |
| basedir                         | /                               |
| big_tables                      | OFF                             |
| binlog_format                   | MIXED                           |
| bulk_insert_buffer_size         | 8388608                         |
| character_set_client            | latin1                          |
| character_set_database          | latin1                          |
| character_set_filesystem        | binary                          |

skip.....

| time_format                     | %H:%i:%s                        |
| time_zone                       | SYSTEM                          |
| timed_mutexes                   | OFF                             |
| tmpdir                          | /tmp                            |
| tx_isolation                    | REPEATABLE-READ                 |
| unique_checks                   | ON                              |
| updatable_views_with_limit      | YES                             |
| version                         | 5.1.25-rc-community             |
| version_comment                 | MySQL Community Server (GPL)    |
| version_compile_machine         | i686                            |
| version_compile_os              | redhat-linux-gnu                |
| wait_timeout                    | 28800                           |
+---------------------------------+---------------------------------+