The syslog-ng 3.0 Administrator Guide

The program() driver starts an external application or script and sends the log messages to its standard input (stdin).

The program() driver has a single required parameter, specifying a program name to start. The program is executed with the help of the current shell, so the command may include both file patterns and I/O redirections. For the list of available optional parameters, see Section 8.2.4, “program()”.

Declaration: 
                program(command_to_run);

	Note
	The syslog-ng application automatically restarts the external program if it exits for reliability reasons. However it is not recommended to launch programs for single messages, because if the message rate is high, launching several instances of an application might overload the system, resulting in Denial of Service.

Note that the message format does not include the priority and facility values by default. To add these values, specify a template for the program destination, as shown in the following example.

	Example 3.21. Using the program() destination driver
	destination d_prog { program("/bin/script" template("<$PRI>$DATE $HOST $MSG\n"); ); };