Timezone specification

[Bryan J Smith]

On Wed, 2008-12-03 at 16:12 -0600, Jason L Tibbitts III wrote:
> I found that with F-10, I can no longer use
>   timezone --utc US/Central
> to specify my timezone.  For some reason this is no longer valid, even
> though it has been a valid timezone for Unix systems since as far as I
> can remember.
> The installer drops me into the timezone chooser, and unfortunately
> that makes it rather difficult to choose a city in US/Central, because
> it either suggests Monterrey (which has different DST rules) or forces
> me to somehow know the myriad DST rules for all of the little cities
> in Indiana which are represented on the map in preference to cities
> like Houston or Dallas.  My complaints about that have always been
> closed NOTABUG, though, so I guess there's no point in complaining
> here, except that I honestly do not know how to specify the proper
> timezone for my location any longer.  Does anyone happen to know?

First off, I absolutely know Anaconda has *0* control over this, but it
is related to the Zoneinfo Data (tzdata) package, which has upstream
considerations (see the following items).  The actual files are
under /usr/share/zoneinfo.  If US/Central does not exist, that's the
root cause.

Second, per Zoneinfo, the standard pathname is region/locale, where the
region is typically continent (or continent set, like "America") and the
locale is the largest city in a that timezone, for the continent.  E.g.,
instead of US/Central, you use America/Chicago.

Third, there are exceptions for regions/countries that use different
offsets or, more commonly, daylight savings time (especially
regions/countries that use a dynamic ruleset, one that is often decided
with little warning).  *AVOID* those unless you need them.  E.g.,
America/Indiana/(city-county), America/Argentina/(city), etc...

WHEN IN DOUBT (short of looking in /usr/share/zoneinfo, the Wikipedia
entry is often updated and typically matches a late tzdata release):  
http://en.wikipedia.org/wiki/List_of_zoneinfo_timezones  

Lastly, Olson, Eggert and the rest of the Zoneinfo gang have long
deprecated many of the compatibility pathnames (e.g., US/Central) and
were trying to purge a lot of the legacy pathnames from their reference
tzdata distribution.  I don't know if they have done that or not more
recently (it's been about 18 months since I have been actively tracking
Zoneinfo developments).  Relying on that long deprecated path is not a
good idea.



-- 
Bryan J Smith - Senior Consultant - Red Hat GPS SE US
mailto:bjs at redhat.com      +1 (407) 489-7013 (Mobile) 
mailto:b.j.smith at ieee.org  (non-RH/ext to Blackberry) 
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