how to relink /bin/sh away from dash -- update-alternatives?

[Robert P. J. Day]

On Wed, 12 May 2010, Tony Arnold wrote:

> Robert,
>
> On 12/05/10 19:09, Robert P. J. Day wrote:
> >
> >    *sigh*.  it's embarrassing to ask trivial questions like this
> > but, sometimes, google just doesn't come through and i'm still
> > feeling my way around ubuntu.
> >
> >    i'm setting up to build openembedded on my lynx box, and the
> > sanity check run by bitbake strongly recommends that i don't leave
> > /bin/sh linked to dash.  currently, there's a symlink /bin/sh ->
> > dash.  but i'm assuming this is managed by the "alternatives"
> > feature, yet:
> >
> > $ sudo update-alternatives --config sh update-alternatives: error:
> > no alternatives for sh. $
> >
> >    what am i screwing up?  i'm just about to run
>
> Nothing. If sh wedre managed by the alternatives system, then
> /bin/sh would link to /etc/alternatives/sh which would link to
> /bin/dash.

  ah, of course, i knew that.  :-)

> Unlinking /bin/sh seems very dangerous to me as sh is needed for the
> boot scripts to run!

  i realize that, which is why i wanted to ask smarter people than me
about it.

> Why does bitbake make this strange recommendation?

  i can ask.  here's the python excerpt from the bitbake sanity
checker code:

try:
            if os.path.basename(os.readlink('/bin/sh')) == 'dash':
                    messages = messages + "Using dash as /bin/sh
causes various subtle build problems, please use bash instead.\n"
except:
                pass



  what the "subtle build problems" are, i have no idea.  i'll see if i
can find out.  beyond that, is there a known reason that /bin/sh
*shouldn't* link to bash?  i can simply readjust the symlink, but
making a change that fundamental makes me nervous.

rday

-- 

========================================================================
Robert P. J. Day                               Waterloo, Ontario, CANADA

            Linux Consulting, Training and Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Twitter:                                       http://twitter.com/rpjday
========================================================================