Re: 4.4 change in behavior from 4.3: how to catch unset when using ${#length}

[Chet Ramey]

On 10/29/16 2:04 AM, L. A. Walsh wrote:
> 
> 
> Chet Ramey wrote:
>> Come on, don't be willfully obtuse. You know better than this. Posix mode
>> doesn't mean "turning it off does everything the way Linda wants."
>>   
> No, but claiming posix as a backing for features running that are
> not running with posix-mode set, is equally obtuse.

I don't think you understand what Posix mode is.

> Bash is not limited to posix features or behavior -- otherwise there
> would not be a "posix"-mode that forces it into posix behavior.

There are indeed several places where the default operation differs from
Posix, and posix mode addresses those. Since bash is basically a posix
shell, though, there are far more places where the bash defaut behavior is
the Posix behavior.  This is one of those places.

> 
> You can claim a feature is a certain way because posix requires it
> when you are operating in posix-only mode.

Not actually true. I can claim bash implements a particular feature the
way bash implements it. You might not agree with it, but the beauty of
open source is that you can take bash, go off, and use it as a base for
`walsh'.

> 
> bash is advertised as having a default operation that differs from
> the POSIX standard.  If someone is not operating in posix mode, then
> it is a "truism", that operations and features in the non-POSIX mode
> might not comply with POSIX.

They might not.  In this case, they do, and the Posix standard is a
good reference for the behavior.

> I'm not being willfully obtuse -- I'm going by the manpage that says
> bash's default differs from the POSIX standard when the posix mode
> is not active:

I'm not sure what you think this is going to demonstrate.  Bash works as
described in the man page.  The man page and the Posix standard happen to
align on this feature.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://cnswww.cns.cwru.edu/~chet/