How to Set or Change the Time Zone in Linux

In Linux, the timezone is the system-wide setting that determines the local time on the system. The timezone is stored in the file `/etc/localtime`, which is a symlink to a file in the `/usr/share/zoneinfo` directory that contains the timezone information.

It is important to set the correct timezone on your Linux system, as this ensures that the system clock is displaying the correct local time. If the timezone is not set correctly, the system clock may be off for several hours, which can cause issues with scheduling tasks, logs, and other applications.

In this article, we will walk through the process of setting or changing the timezone in Linux. We will cover two methods: using the `timedatectl` command and directly modifying the `/etc/localtime` file.

Method 1: Using the `timedatectl` Command

The `timedatectl` command is a utility that allows you to view and modify the system time and timezone settings. The `timedatectl` command is available on most modern Linux distributions, including CentOS, Fedora, Ubuntu, and Debian.

To view the current timezone setting, use the following command:

timedatectl 

The output will look something like this:

Output
                      Local time: Mon 2021-01-18 14:45:34 EST
                  Universal time: Mon 2021-01-18 19:45:34 UTC
                        RTC time: Mon 2021-01-18 19:45:34
                       Time zone: America/New_York (EST, -0500)
       System clock synchronized: yes
systemd-timesyncd.service active: yes
                 RTC in local TZ: no

The Time zone line shows the current timezone setting.

To change the timezone, use the following command:

## Syntax 
timedatectl set-timezone timezone

Replace timezone with the desired timezone. For example, to set the timezone to Asia/Tokyo, use the following command:

timedatectl set-timezone Asia/Tokyo 

This will update the `/etc/localtime` file and set the timezone to Asia/Tokyo.

Method 2: Modifying the `/etc/localtime` File

Another way to set or change the timezone in Linux is to directly modify the `/etc/localtime` file. As mentioned earlier, the `/etc/localtime` file is a symlink to a file in the /usr/share/zoneinfo directory that contains the timezone information. By modifying the `/etc/localtime` file, you can change the timezone setting on the system.

To view the current timezone setting, use the following command:

ls -l /etc/localtime 

The output will look something like this:

Output
lrwxrwxrwx. 1 root root 36 Jan 18 14:45 /etc/localtime -> /usr/share/zoneinfo/America/New_York

The `/usr/share/zoneinfo/America/New_York` file is the current timezone setting.

To change the timezone, you can use the ln command to create a new symlink to a different timezone file in the `/usr/share/zoneinfo` directory. For example, to set the timezone to `Asia/Tokyo`, use the following command:

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

This will update the `/etc/localtime` file and set the timezone to Asia/Tokyo.

Note that you will need to have root privileges to modify the `/etc/localtime` file. You can use the sudo command to execute the ln command as the root user.

I hope this helps you understand how to set or change the timezone in Linux using the `/etc/localtime` file. You can use the `ls -l /usr/share/zoneinfo` command to view a list of available timezone files in the `/usr/share/zoneinfo` directory. Simply replace Asia/Tokyo with the desired timezone file in the ln command to set the timezone to the desired value.

Conclusion

In conclusion, setting or changing the timezone in Linux is an important task that ensures the system clock is displaying the correct local time. There are two methods for setting or changing the timezone in Linux: using the `timedatectl` command and directly modifying the `/etc/localtime` file.

The `timedatectl` command is a utility that allows you to view and modify the system time and timezone settings. To change the timezone using `timedatectl`, use the set-timezone option followed by the desired timezone.

Alternatively, you can change the timezone by modifying the `/etc/localtime` file, which is a symlink to a file in the `/usr/share/zoneinfo` directory that contains the timezone information. To change the timezone using this method, use the ln command to create a new symlink to the desired timezone file in the `/usr/share/zoneinfo` directory.

By following these steps, you can set or change the timezone in Linux and ensure that the system clock is displaying the correct local time.