Re: difference in seconds between two formatted dates ...
On Mon, Dec 18, 2023 at 06:02:48AM +0000, Albretch Mueller wrote:
> On 12/18/23, David Wright <deblis@lionunicorn.co.uk> wrote:
> > Another problem in what you posted is that you sometimes run date
> > in your local timezone (generally for the "now" times), but you
> > append +00:00 as the timezone for those --date strings that you
> > construct from several substrings. You need to use UT throughout.
>
> What difference would that make when all I need is a time difference?
> The way I understand such time format issues is that it needs to just
> be the same in the two dates.
The only advantage of storing timestamps in a human-readable format
would be that you, the human, can read them and know what they mean.
If you wreck this by putting the wrong timezone offset on your
human-readable times, then they're no longer human-readable. So there
is literally NO point in doing all this stupidly difficult formatting and
parsing work, when you could just use seconds-since-epoch format instead.
In addition to that, a case has already been shown where your chosen
format, with or without a fixed timezone offset, is ambiguous -- it
could refer to two different times. This is an issue everywhere
daylight saving time is used. It's rare, but it's real.
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