Re: Switching the default /bin/sh to dash
On Thu, 2009-06-25 at 06:47 +0200, Hendrik Sattler wrote:
> Am Donnerstag 25 Juni 2009 05:21:45 schrieb Raphael Geissert:
> > I just noticed I forgot to say something:
(BTW, scripts not only loads faster under dash, they also run faster in
Dash.)
> > > 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
>
> So that it will be even more strange that a script with bashisms works on some
> Debian Squeeze systems but not on others?
Upgraded systems don't behave exactly like new systems, this isn't
specific for Debian.
The release notes can document those changed behaviors, isn't it? (the
NEWS.Debian too)
And every one RTFM.
> And so that all users that upgrade do not benefit from the goal of this change?
This is the difference between upgrading a system, and installing a new
system:
When upgrading a system, you want your existing applications to keep
working the same way, so you prefer to keep the "backward compatible
way" (see John Goerzen's concerns about "entreprise-made" shell
scripts).
On the other hand, when an application is installed [on a fresh system],
it is ok to introduce new behavior, since it is much more easier to
detect incompatible scripts as you write/install them.
> I usually don't like those not-on-upgrade exceptions.
FYI, I have worked on modular tool (a Posix script;), that can test and
warn such changes on upgraded systems. I would a test for [bd]ash.
http://wiki.debian.org/UpgradeAdvisor
Regards,
Franklin
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