Shell script termination with exit function in backquotes

[Andres Perera]

On Mon, Mar 14, 2011 at 7:46 AM, Maxim Khitrov <max at mxcrypt.com> wrote:
> On Mon, Mar 14, 2011 at 3:16 AM, Andres Perera <andres.p at zoho.com> wrote:
>> On Sun, Mar 13, 2011 at 9:49 PM, Devin Teske <dteske at vicor.com> wrote:
>>> If you make the changes that I've suggested, you'll have consistent execution. The reason you're having inconsistent behavior is because Linux has /bin/sh symbolically linked to /bin/bash while FreeBSD has a more traditional shell (we'll call it bourne shell "plus").
>>
>> that is misleading because command substitutions have traditionally
>> invoked subshells, and freebsd sh(1)/ash is an exception, not the norm
>>
>> in this case, ksh and bash deviates are clearly closer to standard
>> bourne behaviour
>>
>
> Thanks for that explanation. I can understand the benefits of
> optimizing away subshell execution, but that can clearly lead to
> unexpected behavior. Is there some documentation on when this
> optimization is utilized (i.e. the command executed without a
> subshell)? Would I be correct in assuming that it is only restricted
> to built-in commands that are known not to produce any output, such as
> 'exit'?

i would check the source, autoconf docs, and http://www.in-ulm.de/~mascheck/

netbsd has  been patched to fix `exit 1`, according to the last site

>
> - Max
>