IBM Support

Determining time zone for a location

Question & Answer


Question

How can I find out what time zone a location is in? 

Answer

If you need to find the time zone for an unfamiliar location, you can do this by using Red Hat Linux on the NPS host.

The tool you need is zdump. The zdump utility prints the current time in each zone_name named on the command line. It can be found at /usr/sbin/zdump (which is not in the nz user's path).

The zdump tool relies on the zone_name information in /usr/share/zoneinfo which has the timezone information.

A listing of that directory looks like:

    [nz@npshost zoneinfo]$ ls -lah
    total 576K
    drwxr-xr-x   21 root root 4.0K Feb 23  2007 .
    drwxr-xr-x  241 root root  12K Aug  5 15:08 ..
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Africa
    drwxr-xr-x    6 root root 4.0K Feb 23  2007 America
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Antarctica
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Arctic
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Asia
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Atlantic
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Australia
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Brazil
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Canada
    -rw-r--r--    1 root root  755 Mar 17  2006 CET
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Chile
    -rw-r--r--    1 root root  837 Mar 17  2006 CST6CDT
    -rw-r--r--    2 root root  871 Mar 17  2006 Cuba
    -rw-r--r--    1 root root  679 Mar 17  2006 EET
    -rw-r--r--    2 root root  955 Mar 17  2006 Egypt
    -rw-r--r--    2 root root 1.3K Mar 17  2006 Eire
    -rw-r--r--    1 root root   56 Mar 17  2006 EST
    -rw-r--r--    1 root root  837 Mar 17  2006 EST5EDT
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Etc
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Europe
    -rw-r--r--    1 root root  101 Mar 17  2006 Factory
    -rw-r--r--    4 root root 1.3K Mar 17  2006 GB
    -rw-r--r--    4 root root 1.3K Mar 17  2006 GB-Eire
    -rw-r--r--   10 root root   56 Mar 17  2006 GMT
    -rw-r--r--   10 root root   56 Mar 17  2006 GMT0
    -rw-r--r--   10 root root   56 Mar 17  2006 GMT-0
    -rw-r--r--   10 root root   56 Mar 17  2006 GMT+0
    -rw-r--r--   10 root root   56 Mar 17  2006 Greenwich
    -rw-r--r--    2 root root  426 Mar 17  2006 Hongkong
    -rw-r--r--    1 root root   56 Mar 17  2006 HST
    -rw-r--r--    2 root root  429 Mar 17  2006 Iceland
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Indian
    -rw-r--r--    2 root root  630 Mar 17  2006 Iran
    -rw-r--r--    1 root root 4.0K Mar 17  2006 iso3166.tab
    -rw-r--r--    3 root root  803 Mar 17  2006 Israel
    -rw-r--r--    2 root root  185 Mar 17  2006 Jamaica
    -rw-r--r--    2 root root  125 Mar 17  2006 Japan
    -rw-r--r--    2 root root   87 Mar 17  2006 Kwajalein
    -rw-r--r--    2 root root  238 Mar 17  2006 Libya
    -rw-r--r--    1 root root  755 Mar 17  2006 MET
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Mexico
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Mideast
    -rw-r--r--    1 root root   56 Mar 17  2006 MST
    -rw-r--r--    1 root root  837 Mar 17  2006 MST7MDT
    -rw-r--r--    4 root root  877 Mar 17  2006 Navajo
    -rw-r--r--    2 root root  882 Mar 17  2006 NZ
    -rw-r--r--    2 root root  732 Mar 17  2006 NZ-CHAT
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 Pacific
    -rw-r--r--    2 root root  976 Mar 17  2006 Poland
    -rw-r--r--    2 root root 1.3K Mar 17  2006 Portugal
    drwxr-xr-x   19 root root 4.0K Feb 23  2007 posix
    -rw-r--r--    3 root root 1.3K Mar 17  2006 posixrules
    -rw-r--r--    2 root root  165 Mar 17  2006 PRC
    -rw-r--r--    1 root root  837 Mar 17  2006 PST8PDT
    drwxr-xr-x   19 root root 4.0K Feb 23  2007 right
    -rw-r--r--    2 root root  268 Mar 17  2006 ROC
    -rw-r--r--    2 root root  152 Mar 17  2006 ROK
    -rw-r--r--    2 root root  171 Mar 17  2006 Singapore
    -rw-r--r--    3 root root  993 Mar 17  2006 Turkey
    -rw-r--r--    2 root root   56 Mar 17  2006 UCT
    -rw-r--r--    6 root root   56 Mar 17  2006 Universal
    drwxr-xr-x    2 root root 4.0K Feb 23  2007 US
    -rw-r--r--    6 root root   56 Mar 17  2006 UTC
    -rw-r--r--    1 root root  679 Mar 17  2006 WET
    -rw-r--r--    2 root root  815 Mar 17  2006 W-SU
    -rw-r--r--    1 root root  18K Mar 17  2006 zone.tab
    -rw-r--r--    6 root root   56 Mar 17  2006 Zulu

Some of the listings above are a directory that has more time zones in it. For example, the US directory contains the following:
    [nz@helios US]$ ls -lah
    total 112K
    drwxr-xr-x   2 root root 4.0K Feb 23  2007 .
    drwxr-xr-x  21 root root 4.0K Feb 23  2007 ..
    -rw-r--r--   2 root root  856 Mar 17  2006 Alaska
    -rw-r--r--   3 root root  858 Mar 17  2006 Aleutian
    -rw-r--r--   2 root root  130 Mar 17  2006 Arizona
    -rw-r--r--   2 root root 1.3K Mar 17  2006 Central
    -rw-r--r--   3 root root 1.3K Mar 17  2006 Eastern
    -rw-r--r--   4 root root  606 Mar 17  2006 East-Indiana
    -rw-r--r--   2 root root  130 Mar 17  2006 Hawaii
    -rw-r--r--   3 root root  869 Mar 17  2006 Indiana-Starke
    -rw-r--r--   2 root root  811 Mar 17  2006 Michigan
    -rw-r--r--   4 root root  877 Mar 17  2006 Mountain
    -rw-r--r--   2 root root 1017 Mar 17  2006 Pacific
    -rw-r--r--   3 root root  125 Mar 17  2006 Samoa

Here are a few examples of using zdump to find various timezones:
    [nz@npshost]$ /usr/sbin/zdump US/Eastern
    US/Eastern  Mon Aug 31 10:34:12 2009 EDT

    [nz@npshost]$ /usr/sbin/zdump US/Central
    US/Central  Mon Aug 31 09:34:21 2009 CDT

    [nz@npshost]$ /usr/sbin/zdump US/Pacific
    US/Pacific  Mon Aug 31 07:34:31 2009 PDT

    [nz@npshost]$ /usr/sbin/zdump US/Arizona
    US/Arizona  Mon Aug 31 07:34:43 2009 MST

    [nz@npshost]$ /usr/sbin/zdump Japan
    Japan  Mon Aug 31 23:37:36 2009 JST

    [nz@npshost]$ /usr/sbin/zdump Israel
    Israel  Mon Aug 31 17:38:18 2009 IDT

Finally, it is important to note that if your time zone city is in a sub folder under /usr/share/zoneinfo, you must use that syntax with zdump.

For example, if you want the time zone for Riyadh in Saudi Arabia, you must specify the file in the Asia folder or else your results will be incorrect.

Incorrect:
    [nz@npshost Asia]$ /usr/sbin/zdump Riyadh
    Riyadh  Mon Aug 31 14:53:22 2009 Riyadh


Correct:
    [nz@npshost Asia]$ /usr/sbin/zdump Asia/Riyadh
    Asia/Riyadh  Mon Aug 31 17:53:50 2009 AST

[{"Product":{"code":"SSULQD","label":"IBM PureData System"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Component":null,"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"1.0.0","Edition":"","Line of Business":{"code":"LOB10","label":"Data and AI"}}]

Historical Number

NZ603365

Document Information

Modified date:
17 October 2019

UID

swg21571318