How to change time-zone settings from the command line

# sudo dpkg-reconfigure tzdata
-- or --
# sudo ln -sf /usr/share/zoneinfo/America/New_York /etc/localtime
# sudo cat /etc/sysconfig/clock
ZONE="America/New_York"
UTC=true
# sudo reboot

(also check
1) https://askubuntu.com/questions/3375/how-to-change-time-zone-settings-from-the-command-line
2) https://www.digitalocean.com/community/tutorials/how-to-set-up-timezone-and-ntp-synchronization-on-ubuntu-14-04-quickstart
)