How to know when time zone has changed and when timezone will change in linux

sachin

There are timezones where daylight saving time applies due to which timezone changes twice a year which creates problem in few programmes running on the system. I am looking for a way to get when the next timezone change will takes place

sachin

You can use zdump:

NAME
       zdump - timezone dumper

SYNOPSIS
       zdump [ --version ] [ --help ] [ -v ] [ -c [loyear,]hiyear ] [ zonename ... ]

DESCRIPTION
       Zdump prints the current time in each zonename named on the command line.

Example:

zdump -v -c 2023,2025 "Europe/Berlin"

You may reffer https://man7.org/linux/man-pages/man8/zdump.8.html

And to be able to print even in better format, easier to use inside codes and getting the system time zone dynamically, you can use the command (feel free to update as per your requirement).

zdump -v -c 2023,2025 "$(timedatectl | grep 'Time zone' | awk -F ': ' '{print $2}' | awk -F ' ' '{print $1}')" | grep isdst | awk '{print $9","$10","$11","$12","$13","$14","$15}'

sachin

The above command will give the list of dates when timezone changes, you can also try another command in linux.

timedatectl status

This will output all the details you need on timezone

      Local time: Wed 2023-11-22 04:26:14 EST
  Universal time: Wed 2023-11-22 09:26:14 UTC
        RTC time: Wed 2023-11-22 09:26:12
       Time zone: America/New_York (EST, -0500)
     NTP enabled: yes
NTP synchronized: yes
 RTC in local TZ: no
      DST active: no
 Last DST change: DST ended at
                  Sun 2023-11-05 01:59:59 EDT
                  Sun 2023-11-05 01:00:00 EST
 Next DST change: DST begins (the clock jumps one hour forward) at
                  Sun 2024-03-10 01:59:59 EST
                  Sun 2024-03-10 03:00:00 EDT