showing the buffer position in the mode-line

I do quite a bit of scrolling in emacs, but I hardly ever use the scroll bar
for that. The main reason for still having the scroll bar is that it gives me
some indication where I am in the buffer. Of course, there is some information
in the mode-line, and you can get some more with size-indication-mode, but
it's not as immediately obvious as the scroll bar.


But recently, I discovered Lennart Borgman's sml-modeline, which
combines all of the scroll bar information into a nice visual indication on
the modeline, and I have been happily using it, and got rid of my scroll bar.


Put you sml-modeline in your load-path, and the following fragment in your
.emacs should do the trick:

(if (require 'sml-modeline nil 'noerror)    ;; use sml-modeline if available
  (progn 
    (sml-modeline-mode 1)                   ;; show buffer pos in the mode line
    (scroll-bar-mode -1))                   ;; turn off the scrollbar
  (scroll-bar-mode 1)                       ;; otherwise, show a scrollbar...
  (set-scroll-bar-mode 'right))             ;; ... on the right

Note, there is a older version available in Emacswiki which has some problems
(such as conflicting with the Standard ML editing mode for emacs); thus, for
now it's better to us the Launchpad version; the instructions above apply to
that version.

cleaning up buffers automatically

Recently, I discussed some ways to deal with large numbers of buffers. Maybe
we can also take a step back and ask why we have so many buffers in the first
place - do we really need all of them?

Well, the obvious answer is: probably not. After a few days of
(emacs-uptime) there are all kinds of temporary output buffers, man pages
and unchanged buffers you haven't touched in a long time. Let's get rid of
those!

midnight

For this very purpose, emacs provides midnight-mode (as has done so for more
than a decade). At midnight, it looks at all the buffers, and determines which
of the buffers are no longer in use, and closes ('kills') them. Regardless of
its name, this cleanup does not necessarily have to take place at midnight,
but could be invoked at any time.

Setup is easy, just put the following in your .emacs:

(require 'midnight)

Clearly, the package was designed for emacs instances that are running for
long times – for example, by default it clears buffers after having been
inactive for 3 days. I'm not sure if that use case is very common today.
Anyway, you can change it by setting clean-buffer-list-delay-general (which
takes the number of days before a buffer becomes eligible for killing).

You can ask midnight-mode to clean-up unused buffers right now with M-x clean-buffer-list. Also, you can use some variables to control which buffers
are to be killed, and which ones specifically not:

clean-buffer-list-kill-buffer-names
clean-buffer-list-kill-never-buffer-names
clean-buffer-list-kill-regexps
clean-buffer-list-kill-never-regexps

To run clean-buffer-list every n minutes or so, you could use
run-at-time, left as an exercise to the reader.

tempbuf

Another way to accomplish roughly the same is TempbufMode.

It seems a bit better equipped for shorter cleanup interval, and you have some
killed. However, that requires you to add it to the modes where you'd like to
more influence on the algorithm it uses to decide whether a buffer may be use
it, something like:

;; download tempbuf: http://www.emacswiki.org/emacs/tempbuf.el
(when (require 'tempbuf nil 'noerror) 
  (add-hook 'custom-mode-hook 'turn-on-tempbuf-mode)
  (add-hook 'w3-mode-hook 'turn-on-tempbuf-mode)
  (add-hook 'Man-mode-hook 'turn-on-tempbuf-mode)
  (add-hook 'view-mode-hook 'turn-on-tempbuf-mode))

Side-note: I'm using the (when (require 'tempbuf nil 'noerror) ... ) pattern
here to make sure that my .emacs also works when tempbuf is not available.

Added: for cleaning-up your buffer list non-automatically, you can simply
use M-x kill-some-buffers. (Thanks Susan!). Or you can use C-x C-b.