US/Eastern versus America/New_York

Paul Eggert eggert at CS.UCLA.EDU
Wed Aug 17 06:09:14 UTC 2005


John Hawkinson <jhawk at mit.edu> writes:

> Sure. But for the most part, when someone knows what time zone they're
> in, they know they're in US/Eastern, not "the same time zone as New York."

No, I think most new users won't know what "US/Eastern" is.
They'll get a chooser like the tzselect command that is part of
tzcode, and the chooser will walk them through to the correct setting
without their having to know either "US/Eastern" or
"America/New_York".  Once you have a decent chooser, the zone names
are somewhat arbitrary, and we might as well use more-accurate ones.

Another issue is that place names like "New York" tend to be more
stable than time zone labels like "Eastern standard time".  It's
easier for the tz database if we use the more-stable names.  For
example, the most recent change to US time zone labels occurred in
December 2000 (with the introduction of Chamorro standard time), but
since the tz database uses place names this didn't affect users' TZ
settings.

The rest of this message is a sample run of tzselect.  The user input
comes after the '#?'.  Obviously tzselect can be improved upon (and
there are alternate choosers if you don't like tzselect), but it
should illustrate what I'm talking about.

-----

Please identify a location so that time zone rules can be set correctly.
Please select a continent or ocean.
 1) Africa
 2) Americas
 3) Antarctica
 4) Arctic Ocean
 5) Asia
 6) Atlantic Ocean
 7) Australia
 8) Europe
 9) Indian Ocean
10) Pacific Ocean
11) none - I want to specify the time zone using the Posix TZ format.
#? 2
Please select a country.
 1) Anguilla             18) Ecuador              35) Paraguay
 2) Antigua & Barbuda    19) El Salvador          36) Peru
 3) Argentina            20) French Guiana        37) Puerto Rico
 4) Aruba                21) Greenland            38) St Kitts & Nevis
 5) Bahamas              22) Grenada              39) St Lucia
 6) Barbados             23) Guadeloupe           40) St Pierre & Miquelon
 7) Belize               24) Guatemala            41) St Vincent
 8) Bolivia              25) Guyana               42) Suriname
 9) Brazil               26) Haiti                43) Trinidad & Tobago
10) Canada               27) Honduras             44) Turks & Caicos Is
11) Cayman Islands       28) Jamaica              45) United States
12) Chile                29) Martinique           46) Uruguay
13) Colombia             30) Mexico               47) Venezuela
14) Costa Rica           31) Montserrat           48) Virgin Islands (UK)
15) Cuba                 32) Netherlands Antilles 49) Virgin Islands (US)
16) Dominica             33) Nicaragua
17) Dominican Republic   34) Panama
#? 45
Please select one of the following time zone regions.
 1) Eastern Time
 2) Eastern Time - Michigan - most locations
 3) Eastern Time - Kentucky - Louisville area
 4) Eastern Time - Kentucky - Wayne County
 5) Eastern Standard Time - Indiana - most locations
 6) Eastern Standard Time - Indiana - Crawford County
 7) Eastern Standard Time - Indiana - Starke County
 8) Eastern Standard Time - Indiana - Switzerland County
 9) Central Time
10) Central Time - Michigan - Wisconsin border
11) Central Time - North Dakota - Oliver County
12) Mountain Time
13) Mountain Time - south Idaho & east Oregon
14) Mountain Time - Navajo
15) Mountain Standard Time - Arizona
16) Pacific Time
17) Alaska Time
18) Alaska Time - Alaska panhandle
19) Alaska Time - Alaska panhandle neck
20) Alaska Time - west Alaska
21) Aleutian Islands
22) Hawaii
#? 1

The following information has been given:

        United States
        Eastern Time

Therefore TZ='America/New_York' will be used.
Local time is now:      Wed Aug 17 01:51:23 EDT 2005.
Universal Time is now:  Wed Aug 17 05:51:23 UTC 2005.
Is the above information OK?
1) Yes
2) No
#? 1

You can make this change permanent for yourself by appending the line
        TZ='America/New_York'; export TZ
to the file '.profile' in your home directory; then log out and log in again.

Here is that TZ value again, this time on standard output so that you
can use the ./tzselect command in shell scripts:
America/New_York



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