This type of rule is used to add a new line to a text file when the message arrives. There are two parameters:
- File name: the name of the file to which the new line will be added. The file will be created if it doesn't exist. Variable substitution is allowed in this parameter.
- Special case: when the file name contains a sequence of ?'s (question marks), they are replaced with digits to form an unique filename for each new message. Thus if you set file name to «C:\Messages\msg?.txt», the real file name will be msg00001.txt for the first message, msg00002.txt for the second one and so on.
- Log entry format: the template for a new line that will be added. It's just a plain text, possibly containing variable references (you almost certainly need them here).