In the example in ``Structure of rule files'', the action is a single command to run the Edit program with suitable arguments, depending on the files that were dragged onto its icon.
A list of the names of the files dragged onto the icon
is provided in the variable
So, for example, if the icons chapter1 and
chapter2 were dragged onto the Edit
icon the action would be to run the command:
edit -merge chapter1 chapter2