Re: "date -d '-X day' returning wrong day around StandardTime/DaylightTime change-over

[Eric Blake]

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According to Philip Zimmerman (phzimmer) on 3/12/2009 9:10 AM:
> Hello,

Hello Philip,

> 
> I've noticed  a behavior of the 'date' utility as a result of the DST 
> change-over, and was wondering whether this is "expected behavior" or whether 
> this is a problem, so I'm inquiring whether anyone else has noticed this.

Yes.  In fact, so many people have noticed it that it is a FAQ:
http://www.gnu.org/software/coreutils/faq/coreutils-faq.html#The-date-command-is-not-working-right_002e

The issue at hand is that you are dealing with a 23 (or 25) hour day, so
calculations that add or subtract 24 hours will inherently put you 2
calendar days away.  It is not a bug, merely a misunderstanding of how the
tool works.  And changing the behavior to fit your desired needs will
break someone else who has grown accustomed to the current behavior.

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

Eric Blake             address@hidden
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