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From: Eric Blake <ebb9 AT byu DOT net>
Subject:  Re: proposing a new package: dash (shell)
Date: Wed, 4 Mar 2009 18:52:13 +0000 (UTC)
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Akakima <akakima33 <at> gmail.com> writes:

> 
> I would like to see dash (a POSIX-compliant implementation of sh) to 

Not quite POSIX-compliant yet; dash lacks support for LINENO, which is a HUGE 
drawback for what autoconf expects (basically, configure scripts generated by 
autoconf first attempt to find a shell that supports POSIX-mandated LINENO, 
because otherwise it has to run sed to fake LINENO and then re-exec itself, 
which eats precious time).  But other than that, you are correct that dash is 
generally a decent shell, and in many cases faster than bash (it uses some nice 
optimizations to avoid forks).

> be distributed with Cygwin. I am also willing to become the official 
> maintainer if no one else want to do the job.

Yes, a port of dash would be welcome.

> I have done some minimal testing. dash can run its own configure script. In
> order to be sure that dash.exe was the only shell use by cygwin, i copied
> dash.exe over sh.exe and bash.exe.

Are you sure dash was used?  Like I said, configure scripts generated by 
autoconf prefer a shell that supports LINENO, and that means you might have 
ended up with zsh or pdksh doing the work instead of dash.  To guarantee you 
used dash, you can use:

CONFIG_SHELL=path/to/dash path/to/dash ./configure

> 
> I have read somewhere that dash becamed recently the official shell of 
> Ubuntu.

I'm not ready to change the default /bin/sh; I think we'd still like to 
keep /bin/sh as bash for the time being.  But that doesn't stop users from 
installing dash instead of bash as /bin/sh.  And I would particularly welcome a 
pre-built dash, as I already test with it as part of maintaining upstream 
autoconf.

-- 
Eric Blake
volunteer cygwin bash maintainer, upstream autoconf maintainer




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