Setup/ Change Timezone on Linux.

Timezone determines the local time of your location. If you want to change the time zone according to your own preference, Linux provides you with ways to do so; one way through the command line. :~)
Having a correct time zone configured on your Linux data center servers could mean the difference between software running properly or not and as an IT admin, you know the importance of time. Believe it or not, having the correct time on a server is crucial for certain applications and services. Without having time configured properly, you'll receive errors that give you absolutely no indication as to what is causing the problem.
Let’s jump into it!

Checking the Current Timezone

In most other Linux distributions, we can use the date or the timedatectl command to display and set the current system’s time and timezone.

$ date

OUTPUT

Sun 28 Mar 2021 07:17:04 AM UTC

or using the timedatectl command

 $ timedatectl
 
 OUTPUT

 timedatectl
               Local time: Sun 2021-03-28 07:19:51 UTC
           Universal time: Sun 2021-03-28 07:19:51 UTC
                 RTC time: Sun 2021-03-28 07:19:52
                Time zone: Etc/UTC (UTC, +0000)
System clock synchronized: yes
              NTP service: active
          RTC in local TZ: no

As you can see in both outputs above, the timezone is set to UTC.

Set Timezone by changing the symbolic link

The configuration file for timezone is usually located at /etc/localtime which is often a symlink to the file localtime or to the correct time zone file in the system.

$ ls -l /etc/localtime

 OUTPUT

lrwxrwxrwx 1 root root 27 Feb  3 17:53 /etc/localtime -> /usr/share/zoneinfo/Etc/UTC

or 

$ readlink /etc/localtime

OUPUT

../usr/share/zoneinfo/Etc/UTC

The time zone directory is locate at /usr/share/zoneinfo where you can find a list of time zone regions.

$ ls /usr/share/zoneinfo

 OUPUT

Africa      Canada   EST      GMT+0      Iran               Libya      NZ-CHAT     right      Universal
America     CET      EST5EDT  GMT-0      iso3166.tab        localtime  Pacific     ROC        US
Antarctica  Chile    Etc      GMT0       Israel             MET        Poland      ROK        UTC
Arctic      CST6CDT  Europe   Greenwich  Jamaica            Mexico     Portugal    Singapore  WET
Asia        Cuba     Factory  Hongkong   Japan              MST        posix       SystemV    W-SU
Atlantic    EET      GB       HST        Kwajalein          MST7MDT    posixrules  Turkey     zone1970.tab
Australia   Egypt    GB-Eire  Iceland    leapseconds        Navajo     PRC         tzdata.zi  zone.tab
Brazil      Eire     GMT      Indian     leap-seconds.list  NZ         PST8PDT     UCT        Zulu

Now, the solution of changing a timezone becomes a simple exercise of changing the symbolic link from the above directory to the /etc/localtime file. You might need to use the -f flag to force the new link and run the following command as sudo user:

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

Run the date command to verify the change:

$ date

OUTPUT

Sun 28 Mar 2021 05:25:17 PM JST

As you can see in output above, the timezone is set to JST (Japan Standard Time).

Set Timezone by Using the timedatectl Command

Before changing the timezone, you’ll need to find out the long name for the timezone you want to use. The timezone naming convention usually uses a "Region/City" format.
To list all available time zones, you can either list the files in the /usr/share/zoneinfo directory or use the timedatectl command.

$ timedatectl list-timezones

OUTPUT
...
America/Los_Angeles
America/Maceio
America/Managua
America/Manaus
America/Martinique
America/Matamoros
America/Mazatlan
America/Menominee
America/Merida
America/Metlakatla
America/Mexico_City
....

Once you identify which time zone is accurate to your location, run the following command as sudo user:

$ sudo timedatectl set-timezone your_time_zone

For example, to change the system’s timezone to America/Los_Angeles:

$ sudo timedatectl set-timezone America/Los_Angeles

Run the timedatectl command to verify the change:

$ timedatectl

OUTPUT

timedatectl
               Local time: Sun 2021-03-28 01:49:00 PDT
           Universal time: Sun 2021-03-28 08:49:00 UTC
                 RTC time: Sun 2021-03-28 08:49:01
                Time zone: America/Los_Angeles (PDT, -0700)
System clock synchronized: yes
              NTP service: act

As you can see in output above, the timezone is set to PDT (Pacific Daylight Time).

That’s it!! Have yourself a great day.