Re: use of TZ by mktime()/strftime()

[Ed Morton]

On 8/9/2022 12:52 PM, Andrew J. Schorr wrote:
> On Tue, Aug 09, 2022 at 12:17:43PM -0500, Ed Morton wrote:
> > Hmm, I just noticed that `date` behaves the same way gawk does when
> > we set TZ in the environment rather than specify the timezone on the
> > timestamp:
> >
> >     $ TZ=EST date +'%s' -d '2022-01-01T12:00:00'
> >     1641056400
> >
> >     $ TZ=UTC date +'%s' -d '2022-01-01T12:00:00'
> >     1641038400
> >
> >     $ TZ=IST date +'%s' -d '2022-01-01T12:00:00'
> >     1641038400
> >
> >     $ date +'%s' -d '2022-01-01T12:00:00 IST'
> >     1641018600
> >
> > So in the above setting TZ to EST or UTC worked and specifying IST
> > at the end of the timestamp worked, but setting TZ to IST failed
> > just like it does in gawk. Clearly I'm missing something...
> Oops, you beat me to it. Clearly "date -d" understands some time-zone
> abbreviations that don't work when set in the TZ variable.
> You'd need to dig into exactly how "date -d" works.
>
> Regards,
> Andy

Yeah I guess this is part of `date -d`s advertised functionality that it 
can handle a "mostly free format human readable date string".

Sorry for the noise.

    Ed.