GNU bug report logs - #17600
Maybe a bug of `date`

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: HoHo Zhao <hzhao <at> redhat.com>
To: bug-coreutils <at> gnu.org
Subject: Maybe a bug of `date`
Date: Mon, 26 May 2014 16:45:55 +0800

Hi team,

I found this "bug" maybe I am lazy to look through the info document.

Correct:
	$ TZ=UTC date -d "15:00 BST"
	Mon May 26 14:00:00 UTC 2014

Correct:
	$ TZ=UTC date -d "15:00 EST"
	Mon May 26 20:00:00 UTC 2014

Correct:
	$ TZ=UTC date -d "15:00 JST"   (Japan Standard Time)
	Mon May 26 06:00:00 UTC 2014

Wrong:
	$ TZ=UTC date -d "15:00 CST"   (China Standard Time)
	Mon May 26 21:00:00 UTC 2014

So the problem is with "CST" in the date STRING.

Thanks,
-- 
HoHo Zhao
Regional IT Support
Red Hat Greater China

Message #8 received at 17600 <at> debbugs.gnu.org (full text, mbox):

From: Pádraig Brady <P <at> draigBrady.com>
To: HoHo Zhao <hzhao <at> redhat.com>
Cc: 17600 <at> debbugs.gnu.org
Subject: Re: bug#17600: Maybe a bug of `date`
Date: Mon, 26 May 2014 16:57:24 +0100

tag 17600 notabug
close 17600
stop

On 05/26/2014 09:45 AM, HoHo Zhao wrote:
> Hi team,
> 
> I found this "bug" maybe I am lazy to look through the info document.
> 
> Correct:
> 	$ TZ=UTC date -d "15:00 BST"
> 	Mon May 26 14:00:00 UTC 2014
> 
> Correct:
> 	$ TZ=UTC date -d "15:00 EST"
> 	Mon May 26 20:00:00 UTC 2014
> 
> Correct:
> 	$ TZ=UTC date -d "15:00 JST"   (Japan Standard Time)
> 	Mon May 26 06:00:00 UTC 2014
> 
> Wrong:
> 	$ TZ=UTC date -d "15:00 CST"   (China Standard Time)
> 	Mon May 26 21:00:00 UTC 2014
> 
> So the problem is with "CST" in the date STRING.
> 
> Thanks,

I think this is due to the ambiguity of CST.
You're better using unambiguous location based zones

  TZ=UTC date -d 'TZ="Asia/Chongqing" 15:00'

More details at http://www.pixelbeat.org/docs/linux_timezones/

thanks,
Pádraig.

Message #15 received at submit <at> debbugs.gnu.org (full text, mbox):

From: HoHo Zhao <hzhao <at> redhat.com>
To: bug-coreutils <at> gnu.org
Subject: Re: Maybe a bug of `date`
Date: Mon, 26 May 2014 17:36:02 +0800

Hi,

I sent too fast.

Here's the package versions I tested on:
	coreutils-8.21-21.fc20.x86_64
	tzdata-2014c-1.fc20.noarch

And some versions in HREL6 don't work either.

I heard that newer version no longer has this problem, sorry for
troubling. This is the version I heard it works well:
	coreutils-8.22-11.el7.x86_64
	tzdata-2014b-1.el7.noarch

As I saw this problem both exist in Fedora and RHEL, I thought it might
be a problem in the up stream, hence why I shot my mail too fast to you
instead of shooting to Red Hat Bugzilla.


On 2014/5/26 16:45, HoHo Zhao wrote:
> Hi team,
> 
> I found this "bug" maybe I am lazy to look through the info document.
> 
> Correct:
> 	$ TZ=UTC date -d "15:00 BST"
> 	Mon May 26 14:00:00 UTC 2014
> 
> Correct:
> 	$ TZ=UTC date -d "15:00 EST"
> 	Mon May 26 20:00:00 UTC 2014
> 
> Correct:
> 	$ TZ=UTC date -d "15:00 JST"   (Japan Standard Time)
> 	Mon May 26 06:00:00 UTC 2014
> 
> Wrong:
> 	$ TZ=UTC date -d "15:00 CST"   (China Standard Time)
> 	Mon May 26 21:00:00 UTC 2014
> 
> So the problem is with "CST" in the date STRING.
> 
> Thanks,
> 

-- 
HoHo Zhao
Regional IT Support
Red Hat Greater China

Ext. (PEK)83-89380 Tel. +86 10 6533 9380 (Mon, Wed, Thu)
Ext. (NAY)83-88258 Tel. +86 10 6260 8258 (Tue, Fri)

Message #18 received at 17600 <at> debbugs.gnu.org (full text, mbox):

From: Bob Proulx <bob <at> proulx.com>
To: HoHo Zhao <hzhao <at> redhat.com>, 17600 <at> debbugs.gnu.org
Subject: Re: bug#17600: Maybe a bug of `date`
Date: Mon, 26 May 2014 20:55:49 -0600

HoHo Zhao wrote:
> Wrong:
> 	$ TZ=UTC date -d "15:00 CST"   (China Standard Time)
> 	Mon May 26 21:00:00 UTC 2014
> 
> So the problem is with "CST" in the date STRING.

CST in the above is being interpreted as US Central Standard Time.
For Central Standard Time it is correct.

CST is one of the ambiguous timezones that Pádraig referred to.  This
is one of the reasons "date -R" with the unambiguous numeric timezones
is the better output format.

Bob

Message #21 received at 17600 <at> debbugs.gnu.org (full text, mbox):

From: HoHo Zhao <hzhao <at> redhat.com>
To: Bob Proulx <bob <at> proulx.com>, 17600 <at> debbugs.gnu.org
Subject: Re: bug#17600: Maybe a bug of `date`
Date: Tue, 27 May 2014 11:17:38 +0800

Thank you Bob. I got it clear.

On 2014/5/27 10:55, Bob Proulx wrote:
> HoHo Zhao wrote:
>> Wrong:
>> 	$ TZ=UTC date -d "15:00 CST"   (China Standard Time)
>> 	Mon May 26 21:00:00 UTC 2014
>>
>> So the problem is with "CST" in the date STRING.
> 
> CST in the above is being interpreted as US Central Standard Time.
> For Central Standard Time it is correct.
> 
> CST is one of the ambiguous timezones that Pádraig referred to.  This
> is one of the reasons "date -R" with the unambiguous numeric timezones
> is the better output format.
> 
> Bob
> 
> 

-- 
HoHo Zhao
Regional IT Support
Red Hat Greater China

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