Emacs lisp “shell-command-on-region”

Question

In GNU Emacs, I want to run a program, figlet, on the currently selected text. I then want to comment the region which is produced.

I have figured out how to do it using

Answer 1

I'm unsure what you're trying to accomplish with the pushing and popping of the marks, I believe you'd get the same functionality by doing this:

(defun figlet-region (&optional b e) 
  (interactive "r")
  (shell-command-on-region b e "figlet")
  (comment-region b e))

The argument to interactive tells Emacs to pass the region (point and mark) in as the first two arguments to the command.