Re: sort +k

[Eric Blake]

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According to Wayne Power on 6/27/2009 11:52 AM:
> sort: open failed: +1: No such file or directory
> 
> WTF?  sort -k?  Is there any good reason you decided to break every
> every shell script I've written in the last 30 years that uses sort?

Yes, and that reason is POSIX.  Coreutils did not make this change
lightly; the standards committees did and coreutils is downstream from the
standards.

That said, the coreutils documentation mentions this in the NEWS:

|   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
|     tail +4           tail -n +4           tail ./+4
|     tail - f          tail f               [see (*) below]
|     tail -c 4         tail -c 10 ./4       tail -c4
|     touch 12312359 f  touch -t 12312359 f  touch ./12312359 f
|     uniq +4           uniq -s 4            uniq ./+4
|
|     (*) "tail - f" does not conform to POSIX 1003.1-2001; to read
|     standard input and then "f", use the command "tail -- - f".
|
|   These changes are in response to decisions taken in the January 2005
|   Austin Group standardization meeting.  For more details, please see
|   "Utility Syntax Guidelines" in the Minutes of the January 2005
|   Meeting <http://www.opengroup.org/austin/docs/austin_239.html>.

You may also find it informative to read: 'info coreutils standards'.

> Is this a special version for Apple to piss off old unix folks, or did
> you break this command for everybody?

Because of POSIX, using 'sort +1' is inherently non-portable for everyone.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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