- Red Hat Enterprise Linux (RHEL) 4
- Red Hat Enterprise Linux (RHEL) 5
- Red Hat Enterprise Linux (RHEL) 6
- How to check if the timezone data has the right daylight savings or summer time changeover dates?
- How to check the offset and drift values for
The timezone information, including changeover dates for daylight savings and summer time (DST), is included in the tzdata package.
The Time Zone Database contains code and data that represent the history of local time for many representative locations around the globe.
It is updated periodically to reflect changes made by political bodies to time zone boundaries, UTC offsets, and daylight-saving rules.
Check the version of the
tzdatapackage which is installed on the machine, with the following command:
# rpm -q tzdata tzdata-2009u-1.el5
This reports the year and revision of the files in use and it means that the installed timezone files date from 2009, and are at revision u.
To view the changeover dates for DST in a particular timezone:
# zdump -v /usr/share/zoneinfo/<Region>/<Timezone> | grep <year>
- This will give a list of the changeover dates such as the following:
# zdump -v /usr/share/zoneinfo/America/Los_Angeles | grep 2010 /usr/share/zoneinfo/America/Los_Angeles Sun Mar 14 09:59:59 2010 UTC = Sun Mar 14 01:59:59 2010 PST isdst=0 gmtoff=-28800 /usr/share/zoneinfo/America/Los_Angeles Sun Mar 14 10:00:00 2010 UTC = Sun Mar 14 03:00:00 2010 PDT isdst=1 gmtoff=-25200 /usr/share/zoneinfo/America/Los_Angeles Sun Nov 7 08:59:59 2010 UTC = Sun Nov 7 01:59:59 2010 PDT isdst=1 gmtoff=-25200 /usr/share/zoneinfo/America/Los_Angeles Sun Nov 7 09:00:00 2010 UTC = Sun Nov 7 01:00:00 2010 PST isdst=0 gmtoff=-28800
If there are any discrepancies between the changeover dates listed on the system and the expected changeover dates, update to the latest version of
For RHEL 4:
# up2date tzdata
- For RHEL 5 and RHEL 6:
# yum -y update tzdata
- Red Hat Enterprise Linux
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