RE: [External] : Re: Provide numerical argument to indent-rigidly-right

[Drew Adams]

> Calling with negative arg
> M-- 4 indent-rigidly RET has no effect here. Bug?

Did you select the text to outdent (i.e., active
region)?  Did you use `M-- 4 C-x TAB'?

If not, there's your problem.
If yes, `M-x report-emacs-bug'.

> If called interactively with no prefix argument, activate a
> transient mode in which the indentation can be adjusted interactively
> by typing <left>, <right>, S-<left>, or S-<right>.
> Typing any other key exits this mode, and this key is then
> acted upon as normally.
> 
> That's too complex for such a simple thing.

Is using a prefix arg too complex?  You're not
obliged to use incremental indenting/outdenting.