Alright, I solved it.

The problem is that emacs' shell-command doesn't use the same environment,
so it wasn't picking up the value of those three vars:

✗ export | grep UTF
    LANG=en_US.UTF-8
    LC_ALL=en_US.UTF-8
    LC_CTYPE=en_US.UTF-8

So, I did this:

(defun test ()
  (setenv "LANG" "en_US.UTF-8")
  (setenv "LC_ALL" "en_US.UTF-8")
  (setenv "LC_CTYPE" "en_US.UTF-8")
        (shell-command  "/Users/myself/.rvm/bin/rvm ruby-1.9.3-p194 do
/usr/bin/rubyscript")
        )

And now it works fine.

Cheers,

- Marcelo.

On Thu, Aug 30, 2012 at 6:01 PM, Marcelo de Moraes Serpa <
celoserpa@gmail.com> wrote:

> Hi Peter,
>
> Thanks for the reply.
>
> I've changed the func argument to 'utf-8-unix and it did not make a
> difference. Same error.
>
> - Marcelo.
>
>
> On Thu, Aug 30, 2012 at 4:16 PM, Peter Dyballa <Peter_Dyballa@web.de>wrote:
>
>>
>> Am 30.08.2012 um 19:41 schrieb Marcelo de Moraes Serpa:
>>
>> > By the way, I forgot to say that I have added the "(let
>> > (universal-coding-system-argument 'us-ascii-mac))" in an attempt to fix
>> it,
>> > but it made no difference whatsoever.
>>
>> Have you tried an UTF encoding? I think Ruby isn't as primitive as
>> US-ASCII…
>>
>> --
>> Greetings
>>
>>   Pete
>>
>> We are usually convinced more easily by reasons we have found ourselves
>> than by those which have occurred to others.
>>                                 – Blaise Pascal
>>
>>
>