Dash as default shell

Zdenek Kabelac zkabelac at redhat.com
Mon Oct 6 06:57:09 UTC 2014

Dne 6.10.2014 v 08:06 Paolo Bonzini napsal(a):
> Il 02/10/2014 11:04, Zdenek Kabelac ha scritto:
>> It used to give significant boost for automake & libtool based software
>> - however at some point libtool started to use bashisms and so you
>> cannot just replace  /bin/sh -> dash - as build will fail.
> This is wrong.
> libtool detects whether you can use bashisms, and falls back to POSIX
> shell constructs if it cannot use them.  The non-POSIX constructs are
> usually faster because they do not need to fork() the shell.  Autoconf
> does the same.  dash rejects some of these constructs, and accept others.
> Before Autoconf started doing this, dash was indeed quite a bit faster
> than bash on configure scripts.  So your estimate of 50% is valid for
> projects on which Autoconf has last been run 7-8 years ago.

Well all I can say is autoconf (at least on my rawhide) doesn't work with dash 
for quite some time.

So yes - I admit my numbers are dated. But purely because I cannot revalidate 


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