On 04/04/2016 12:09 AM, Yaakov Selkowitz wrote:
> On 2016-04-03 18:05, Andrey Repin wrote:
>> Because, within my reach, Cygwin is the only system that not using
>> DASH as
>> /bin/sh. Though, I may try rolling some busybox…
> 
> There *is* a world outside of Debian/Ubuntu; Fedora, RHEL/CentOS, and
> Arch Linux all use bash for /bin/sh.  However, a simple test in the form
> of building GCC with dash as /bin/sh, while noticeably faster, showed
> that Debian/Ubuntu have yet to fully upstream their work
> ("gcc/genmultilib: 261: shift: can't shift that many").

And non-Linux systems use a completely different shell for /bin/sh
(neither dash nor bash; BSD systems tend to use mksh).

> 
> As much as the speed difference is promising (and frankly tempting), I'm
> afraid we simply don't have the resources to fix everything to work with
> dash as /bin/sh.

That's why the alternatives would default to cygwin using bash as
/bin/sh, and anyone flipping the alternative to dash is on their own if
things break (or better, can help submit patches upstream to the
multiple places that are broken by using non-POSIX constructs in scripts
run by /bin/sh).

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org