In article <mailman.27.1368871635.22516.help-gnu-emacs@gnu.org>,
 Peter Dyballa <Peter_Dyballa@Web.DE> wrote:

> Am 17.05.2013 um 23:07 schrieb Doug Lewan:
> 
> > I see a problem when M-x find-file is expanding ${VARIABLE} but not taking 
> > it from the newly defined environment variable. Everything else picks it up 
> > (I presume just via fork/exec).
> > 
> > I hope this script is clearer.
> > 
> > In shell:
> >    $ echo ${VARIABLE}
> >    /a/very/long/path
> >    $ emacs &
> > Inside emacs:
> >    C-x C-f ${VARIABLE}/to/work                <== Finds 
> >    "/a/very/long/path/to/work".
> >    (setenv "VARIABLE" "/shorter/path")
> >        => "/shorter/path"
> >    M-! echo ${VARIABLE}
> >    "/shorter/path"
> >    M-x shell
> > In shell inside emacs:
> >    $ echo ${VARIABLE}
> >    "/shorter/path"
> > Back in emacs:
> >    C-x C-f ${VARIABLE}/to/Grandmothers/house
> > This finds the file "/a/very/long/path/to/Grandmothers/house", where I sort 
> > of expect it to find "/shorter/path/to/Grandmothers/house".
> 
> No, this cannot work in GNU Emacs with a regular *shell* buffer ­ maybe it 
> works in VIM?
> 
> GNU Emacs is a host (or a PC) that allows other programmes to run inside it. 
> Every variable the external (whatsoever: Korn, Bourne, C, Š) shell 
> interpreter is setting, is a private variable of and only inside this shell 
> interpreter. And since it's just a shell interpreter it has no access to the 
> variables of GNU Emacs. No shell function exists for this purpose.

But if you do:

M-: (setenv "VARIABLE" "/shorter/path")

inside Emacs, you're setting an environment variable in the Emacs 
process, not just within a program that's hosted by Emacs.

-- 
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***