How to change system timezone in Ubuntu

The system timezone in Ubuntu is initially configured during installation, usually based on the system's geographical location. This setting ensures smooth operation of time-dependent services, including cron jobs.

Ubuntu manages the system timezone through the /etc/localtime file, which is a symbolic link to a timezone data file located in the /usr/share/zoneinfo directory. Changing the timezone involves updating this symbolic link to the appropriate timezone file.

The timedatectl command is typically used to modify the system timezone on an Ubuntu server or desktop. This command allows users to check the current timezone, list all available timezones, and easily set a new timezone. Alternatively, users can directly manipulate the symbolic link in /etc/localtime to point to a different timezone file in /usr/share/zoneinfo. The timedatectl command is preferred for its simplicity and ease of use.

1. Launch the terminal.
2. Check the currently used timezone using timedatectl.

   $ timedatectl
                  Local time: Mon 2024-05-06 19:06:41 +08
              Universal time: Mon 2024-05-06 11:06:41 UTC
                    RTC time: Mon 2024-05-06 11:06:42
                   Time zone: Asia/Kuala_Lumpur (+08, +0800)
   System clock synchronized: no
                 NTP service: active
             RTC in local TZ: no

3. List available timezones in the system using timedatectl.

   $ timedatectl list-timezones
   Africa/Abidjan
   Africa/Accra
   Africa/Addis_Ababa
   Africa/Algiers
   Africa/Asmara
   Africa/Asmera
   Africa/Bamako
   Africa/Bangui
   Africa/Banjul
   Africa/Bissau
   Africa/Blantyre
   Africa/Brazzaville
   Africa/Bujumbura
   Africa/Cairo
   Africa/Casablanca
   Africa/Ceuta
   Africa/Conakry
   Africa/Dakar
   Africa/Dar_es_Salaam
   Africa/Djibouti
   ##### snipped 

4. Search for your timezone from the list of available timezones.

   $ timedatectl list-timezones | grep -i tokyo
   Asia/Tokyo

5. Set the new timezone using timedatectl.

   $ sudo timedatectl set-timezone Asia/Tokyo
   [sudo] password for user:

   The above command is similar to doing the following two manual steps:

   1. Unlink your currently-used timezone.

      $ sudo unlink /etc/localtime
      [sudo] password for user:

   2. Link /etc/localtime to your new timezone.

      $ sudo ln -s /usr/share/zoneinfo/Asia/Tokyo /etc/localtime

6. Confirm the changes using timedatectl.

   $ timedatectl
                  Local time: Mon 2024-05-06 20:09:09 JST
              Universal time: Mon 2024-05-06 11:09:09 UTC
                    RTC time: Mon 2024-05-06 11:09:10
                   Time zone: Asia/Tokyo (JST, +0900)
   System clock synchronized: no
                 NTP service: active
             RTC in local TZ: no