* lisp/progmodes/executable.el (executable-self-display):

Use non-obsolete tail syntax.  (Bug#20779)
(executable-self-display): Doc update.

lisp/progmodes/executable.el

@@ -104,7 +104,7 @@ Typical values are 73 (+x) or -493 (rwxr-xr-x)."
 (defvar executable-command nil)
 
 (defcustom executable-self-display "tail"
-  "Command you use with argument `+2' to make text files self-display.
+  "Command you use with argument `-n+2' to make text files self-display.
 Note that the like of `more' doesn't work too well under Emacs \\[shell]."
   :type 'string
   :group 'executable)
@@ -258,7 +258,7 @@ The magic number of such a command displays all lines but itself."
   (interactive)
   (if (eq this-command 'executable-self-display)
       (setq this-command 'executable-set-magic))
-  (executable-set-magic executable-self-display "+2"))
+  (executable-set-magic executable-self-display "-n+2"))
 
 ;;;###autoload
 (defun executable-make-buffer-file-executable-if-script-p ()