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Date: Tue, 28 Feb 2017 10:12:47 +1100
From: Duncan Roe <duncan_roe AT acslink DOT net DOT au>
To: cygwin AT cygwin DOT com
Subject: Re: [ANNOUNCEMENT] Updated: dash-0.5.9.1-1
Message-ID: <20170227231247.GA19383@dimstar.local.net>
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On Sat, Feb 25, 2017 at 09:08:55AM -0800, Steven Penny wrote:
> On Sat, 25 Feb 2017 11:46:08, cyg Simple wrote:
> > If *your* script has a dependency to run using *dash* instead of *sh*
> > then you _must_ use #!/bin/dash anyway.
>
> I think you have a fundamental misunderstanding of what Dash is. Dash is a
> minimal shell, similar to the "sh" defined by POSIX:
>
> http://pubs.opengroup.org/onlinepubs/9699919799/utilities/sh.html
>
> So saying "a dependency to run using *dash*" makes about as much sense as saying
> "Cygwin has a dependency to run using Cygwin".
>
> > And what I _*I*_ don't want dash as /bin/sh? You see not everyone in the
> > community will agree.
>
> With respect to the community, yes of course you get a say. If the community
> doesn???t agree on this we will continue to use Bash. However you do not get a say
> with respect to the standard. The POSIX standard specified that /bin/sh is the
> shell I have linked above. Bash is a superset of that, so by definition those
> extra features are not defined or guaranteed to exist. When writing /bin/sh
> scripts, you should be assuming the users /bin/sh only has those features
> defined by POSIX. Example:
>
> #!/bin/bash -> script that follows might have Bashisms
> #!/bin/dash -> script that follows might have Dashisms (echo -n, local)
> #!/bin/sh -> script that follows should be a POSIX script
>
> > You can make the suggestion to those using your script to do so otherwise but
> > forcing dash as /bin/sh worldwide isn't something you can actually do.
>
> Yes we certainly can. Debian and Ubuntu have already done this.
>
"we" being you and who else?

/bin/sh has been bash for a long time and I would prefer it stays that way.

OTOH, I have started prefacing scripts with

   /bin/bash -p

to be on the safe side. "-p" stops bash from importing functions from the
environment BTW

Cheers ... Duncan.

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