RE: viewing MS powerpoint files from dired

[Drew Adams]

> I could not find dired-guess-shell-alist-user in my emacs, or any
> other such variables.  I found a few dired hooks.  I will look into
> that.

You need to load `dired-x.el' for that user option.

,----
| dired-guess-shell-alist-user is a variable defined in `dired-x.el'.
| 
| User-defined alist of rules for suggested commands.
| These rules take precedence over the predefined rules in the variable
| `dired-guess-shell-alist-default' (to which they are prepended).
| 
| Each element of this list looks like
| 
|     (REGEXP COMMAND...)
| 
| where each COMMAND can either be a string or a Lisp expression that evaluates
| to a string.  If several COMMANDs are given, the first one will be the default
| and the rest will be added temporarily to the history and can be retrieved
| with M-x previous-history-element (M-p) .
| 
| The variable `dired-guess-shell-case-fold-search' controls whether
| REGEXP is matched case-sensitively.
| 
| You can set this variable in your ~/.emacs.  For example, to add rules for
| `.foo' and `.bar' files, write
| 
|  (setq dired-guess-shell-alist-user
|        (list (list "\\.foo\\'" "FOO-COMMAND");; fixed rule
|               ;; possibly more rules ...
|               (list "\\.bar\\'";; rule with condition test
|                     '(if condition
|                           "BAR-COMMAND-1"
|                         "BAR-COMMAND-2"))))
`----