Re: Switching the default /bin/sh to dash

["Giacomo A. Catenazzi" <cate@debian.org>]

Steve Langasek wrote:
> On Wed, Jun 24, 2009 at 10:21:45PM -0500, Raphael Geissert wrote:
> > I just noticed I forgot to say something:
>
> > > What won't change:
> > > * Bash will still be used as the default interactive shells for users
> > * the sh symlink won't be modified on existing installations
>
> I understand the concerns about not breaking existing scripts, but I'll
> nevertheless be disappointed if this switch isn't made on upgrades as well.
> Using bash as /bin/sh causes a number of subtle problems for shutdown
> sequences, in addition to the obvious performance issues, and I think the
> fix for non-POSIX shell scripts is straightforward enough that we should
> just document the change (in the release notes and NEWS.Debian) and tell
> users to use the right interpreter if they have any doubts about their
> dash-compatibility.

Hmm, so a switch to dash it is not because of POSIX, but because
of "better code" and lighter shell for our scripts?

Which is also a good reason for the change.

But could you tell us more about the "subtle problems for shutdown
sequences".

The bash can simulate the init program, which is very good for
system management on emergencies or debug the init procedure.
(I don't know about dash)
These are special cases, but it would nice if we support or document the
strange iterations of bash (and maybe also of busibox) on init procedures.

ciao
	cate