Changing or Updating the time zone in Ubuntu Server

  There are quite a few reasons you may find that you need to change your time zone – for example, if you’re using a pre-made image for a virtual machine you may find that the default timezone is not set to your country. You can change the time manually, though there is a quick and easy way:  
sudo dpkg-reconfigure tzdata  
This reconfigures the tzdata (timezone data) package and runs you through a series of prompts asking which country/city you live in, and updates the time accordingly.   You can check the current system time with:  
date
  to verify that it worked!