If I write a command that calls
(interactive "f"), Emacs will prompt the user to select a file when the command is run interactively. With Helm enabled, this selection is done through Helm with no additional effort -- this is great!
However, if I mark multiple files in the Helm selection window, it is not clear to me that this information is passed on to the command. Is there a way to get custom commands to cooperate with Helm and multiple selections?