[debbugs-tracker] bug#14146: closed ([date command] Possible bug)

[GNU bug Tracking System]

Your message dated Fri, 05 Apr 2013 09:24:27 -0600
with message-id <address@hidden>
and subject line Re: bug#14146: [date command] Possible bug
has caused the debbugs.gnu.org bug report #14146,
regarding [date command] Possible bug
to be marked as done.

(If you believe you have received this mail in error, please contact
address@hidden)


-- 
14146: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=14146
GNU Bug Tracking System
Contact address@hidden with problems

--- Begin Message --- Subject: [date command] Possible bug Date: Fri, 5 Apr 2013 11:13:04 +0200

Good morning,

for the 1th of April 2013 the command date has this interesting behaviour:

$ date

Mon Apr  1 00:22:31 CEST 2013

$ date -d 'yesterday'

Sat Mar 30 23:22:38 CET 2013

As you can read the date is 30 March instead of 31 the time 23:22 instead of 00:22

I could verify that on:

• my personal machine running:
  Linux dip03-ubu 3.2.0-40-generic-pae #64-Ubuntu
  date --version: date (GNU coreutils) 8.13
• production servers running:
  Linux ecomappsrv01 2.6.38-8-generic-pae #42-Ubuntu
  date --version: date (GNU coreutils) 8.5

That doesn't happen for year 2012 and 2014.

It happens even using -u option.

It does not happen forcing date:

date -d '2013-04-01 00:22:00 1 day ago' 

Sun Mar 31 00:22:00 CET 2013

If you need more information just ask and I will try to respond as soon as possible.

Thank you, best regards.

Ivan Lombardi Borgia

--- End Message ---

--- Begin Message --- Subject: Re: bug#14146: [date command] Possible bug Date: Fri, 05 Apr 2013 09:24:27 -0600 User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130311 Thunderbird/17.0.4

tag 14146 notabug
thanks

On 04/05/2013 03:13 AM, Ivan Lombardi Borgia wrote:
> Good morning,
> 
> for the 1th of April 2013 the command *date *has this interesting behaviour:
> *
> *
> *$ date*
> *Mon Apr  1 00:22:31 CEST 2013*
> *$ date -d 'yesterday'*
> *Sat Mar 30 23:22:38 CET 2013*

Did you notice the change in the time zone name from CEST to CET, based
on daylight savings?

> That doesn't happen for year 2012 and 2014.

Yeah, because daylight savings in your timezone falls on a different
date in those years.

> If you need more information just ask and I will try to respond as soon as
> possible.

You are hitting a typical usage problem.  This is not a bug in date, but
in your usage of it; you are failing to account that "yesterday"
translates to "24 hours ago", but that 24 hours ago close to midnight
when crossing over a 23-hour day (thanks to daylight savings) can cross
2 calendar days.

For more information, including the tip to base relative date
computation on noon instead of close to midnight, see the FAQ:

https://www.gnu.org/software/coreutils/faq/coreutils-faq.html#The-date-command-is-not-working-right_002e

As such, I'm closing this as not a bug, although you may feel free to
continue replying if you have further questions.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

signature.asc
Description: OpenPGP digital signature

--- End Message ---