   (dwim-shell-command--on-marked-files
    "Convert to mp3"
    "ffmpeg -stats -n -i <<f>> -acodec libmp3lame <<fne>>.mp3"
-   :check-utils "ffmpeg"))
+   :utils "ffmpeg"))
 
 (defun dwim-shell-command-convert-image-to-jpg ()
   "Convert all marked images to jpg(s)."

    (seq-do (lambda (util)
              (cl-assert (executable-find util) nil
                         (format "%s not installed" util)))
            check-utils)
    (with-current-buffer proc-buffer
      (require 'shell)
      (shell-mode))

   (format "qpdf --verbose --encrypt '%s' '%s' 256 -- <<f>> <<fne>>_enc.<<e>>"
           (read-passwd "user-password: ")
           (read-passwd "owner-password: "))
   :utils "qpdf"))

(defun dwim-shell-command--gifsicle-frames-every (skipping-every file)
  (string-join
