How to change time-zone settings from the command line

I have a virtual machine that is set to PST that a couple of colleagues have in different time-zones.

If I wanted to change the time-zone to EST and GMT, what do I need to do?

Use timedatectl

sudo timedatectl set-timezone <timeszone>

Examples:

• Timezone as EST

  sudo timedatectl set-timezone EST
  

• Timezone as UTC

  sudo timedatectl set-timezone UTC
  

• Listing all valid Timezones

  timedatectl list-timezones
  

This command is perfect for automation scripts since it doesn't require any user interaction while compared to the other given answer based on dpkg-reconfigure tzdata.

As root you have to execute:

dpkg-reconfigure tzdata

A menu based tool should be started that allows you to change the timezone.

The following also work. For GMT:

ln -sf /usr/share/zoneinfo/GMT /etc/localtime

For EST:

ln -sf /usr/share/zoneinfo/EST /etc/localtime

The most ease way especially to a server is to list timezones:

timedatectl list-timezones

And choose yours, for example:

timedatectl set-timezone Europe/Athens

Thats it! , :-)