bug#14545: date --iso-8601 should use colon in time zone offset

[Jim Meyering]

Paul Eggert wrote:

> On 06/02/2013 09:13 PM, Jordon Kalilich wrote:
>> The output mostly follows the ISO 8601:2004 extended format but
>> fails to include
>> a colon in the time zone offset, as required by section 4.3.2 "Complete
>> representations" and section 4.3.3 "Representations other than complete."
>
> If memory serves the --iso-8601 option conformed to ISO 8601
> a while ago, but the ISO standard changed.  At any rate, the
> --iso-8601 option has been deprecated since 2005.  Hmm, I
> see that this has not been reflected in the documentation, so
> perhaps that's the next step to take for this option, on its
> way out the door.
>
> You can get the effect you want, with the command
>
> date +'%Y-%m-%dT%H:%M:%S.%N%:z'

It was undocumented until late 2011's v8.14-17-g2f1384b,
when I undeprecated it.  Here's the commit log entry:

    date: reinstate the --iso-8601 (-I) option

    We deprecated and undocumented the --iso-8601 (-I) option mostly
    because date could not parse that particular format.  Now that
    it can, it's time to restore the documentation.
    * src/date.c (usage): Document it.
    * doc/coreutils.texi (Options for date):
    Reinstate documentation.
    Reported by Hubert Depesz Lubaczewski in http://bugs.gnu.org/7444.

Now that we know the standard has evolved, I'm inclined to conform.