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From: vallor <vallor@cultnix.org>
Newsgroups: comp.os.linux.advocacy
Subject: Re: Does Dimdows Know What Time It Is?
Date: 28 Sep 2024 23:21:43 GMT
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On Sat, 28 Sep 2024 22:40:24 -0000 (UTC), Lawrence D'Oliveiro
<ldo@nz.invalid> wrote in <vda0ko$1e457$1@dont-email.me>:

> Something Unix did that was different from most other OSes was, its
> system clock kept time in UTC (or GMT, in pre-UTC days). Linux does the
> same.
> When you use a command like “date” to see what the current date and time
> is, it converts that UTC time to a local time in some specified
> timezone. Changing the timezone is as easy as specifying a new value for
> the TZ environment variable.
> 
> Windows, on the other hand, keeps its system clock in local time, in
> some specific time zone that is assumed to apply systemwide.
> 
> This is a particularly dumb idea when you realize how much it
> complicates things if your time zone has daylight saving time. We have
> seen this sort of thing happen on Windows systems before, where they
> might forget to adjust the clock to start/stop daylight saving, or even
> adjust it twice so you end up being an hour off in the opposite
> direction.
> 
> This can’t happen on Linux systems, because there is no turning daylight
> saving “on” or “off” as such: there is simply a table of local time
> offsets (from the “tzdata” files), and the correct offset to apply
> depends only on the actual UTC time value, not on the current setting of
> any system flag.
> 
> This also makes it easy to convert between UTC and local times at any
> time in the past, for any time zone.

$ echo $TZ

$ ls -l /etc/localtime
lrwxrwxrwx 1 root root 39 Jul 16 07:50 /etc/localtime -> /usr/share/zoneinfo/America/Los_Angeles

-- 
-v