When invoked with a prefix argument, the command will receive all
open messages in the current thread (formatted as an mbox) rather
than only the current message."
- (interactive "P\nsPipe message to command: ")
+ (interactive (let ((query-string (if current-prefix-arg
+ "Pipe all open messages to command: "
+ "Pipe message to command: ")))
+ (list current-prefix-arg (read-string query-string))))
(let (shell-command)
(if entire-thread
(setq shell-command