Subject: Re: bug#5944: sort with option +4nr does not work now and it used to do it some time ago

From: Eric Blake <[email-masked]>
Date: Wed, 14 Apr 2010 07:58:09 -0600

On 04/14/2010 02:13 AM, Martinez, Abel wrote:
> Hi CoreUtil/SORT developer team:
> 
> Long time ago I used cygwing to sort file's content by the text
> available on its 4th column in reverse order (under bash) using ___$sort
> +4nr file.txt____ .
> 
> I have tried now same function with the latest cygwing and coreutils
> sorting package (sort.exe 19-March-2010) and with those options does not
> work; It says:
> 	$ sort +4nr ACCESS.txt
> 	sort: open failed: +4nr: No such file or directory

Not a bug, but a difference in the level of POSIX compliance.  Older
cygwin defaulted to the 1992 version of POSIX, while newer cygwin
defaults to 2001.  Per the NEWS file:

>   A few usages still have behavior that depends on which POSIX standard is
>   being conformed to, and portable applications should beware these
>   problematic usages.  These include:
> 
>     Problematic       Standard-conforming replacement, depending on
>        usage            whether you prefer the behavior of:
>                       POSIX 1003.2-1992    POSIX 1003.1-2001
>     sort +4           sort -k 5            sort ./+4

You can learn more about this, as well as a way to use the
_POSIX2_VERSION environment variable to select an alternate behavior, by
reading 'info coreutils standards'.

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-- 
Eric Blake   [email-masked]    +1-801-349-2682
Libvirt virtualization library http://libvirt.org