ibuffer-auto-mode
ibuffer-auto-mode is an interactive autoloaded compiled Lisp function in `ibuf-ext.el
'.
(ibuffer-auto-mode &optional ARG)
Toggle use of Ibuffer's auto-update facility (Ibuffer Auto mode).
With a prefix argument ARG, enable Ibuffer Auto mode if ARG is
positive, and disable it otherwise. If called from Lisp, enable
the mode if ARG is omitted or nil.