- Check 
general_logflag: 
mysql> SHOW VARIABLES LIKE "general_log%";
+------------------+----------------------------+
| Variable_name    | Value                      |
+------------------+----------------------------+
| general_log      | OFF                        |
| general_log_file | /var/run/mysqld/mysqld.log |
+------------------+----------------------------+
- Enable/disable: 
mysql> SET GLOBAL general_log = 'ON';