$ /etc/init.d/mysql reload
$ sudo /etc/init.d/mysql force-reload
mysql> SHOW VARIABLES LIKE 'wait_timeout';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout | 28800 |
+---------------+-------+
28800 is seconds, which is 8 hours
mysql> SELECT @@global.wait_timeout, @@session.wait_timeout;
To update:
SET GLOBAL wait_timeout=300
or
set @@global.wait_timeout = 400;
or
mysql -uroot -e"SET GLOBAL wait_timeout=5; SET GLOBAL interactive_timeout=5"
mysql -uroot -e"SET GLOBAL wait_timeout=9000; SET GLOBAL interactive_timeout=5000"