The configuration file has a very simple format. Each line describes an action; if a line begins with a whitespace, it is considered a continuation of the previous line. Lines beginning with # are considered as comments.
Each line has four parts: a name of a USB HID item, a value for that item, a debounce value, and an action. There must be whitespace between the parts.
The item names are similar to those used by usbhidctl(1), but each part must be prefixed by its page name.
The value is simply a numeric value. When the item reports this value, the action will be performed. If the value is *, it will match any value.
The debounce value is an integer not less than 0. The value of 0 indicates that no debouncing should occur. A value of 1 will only execute the action when the state changes. Values greater than one specify that an action should be performed only when the value changes by that amount.
The action is a normal command that is executed with system(3). Before it is executed some substitution will occur: $n will be replaced by the n th argument on the command line, $V will be replaced by the numeric value of the HID item, $N will be replaced by the name of the control, and $H will be replaced by the name of the HID device.