SET TimeZone on Ubuntu19 with Command Line

:Find Current TimeZone
$ timedatectl list-timezones | grep -i [zone]

ex:
$ timedatectl list-timezones | grep -i europe

:Remove link
$ sudo unlink /etc/localtime

:Set new TimeZone
sudo ln -s /usr/share/zoneinfo/[Zone/TimeZone] /etc/localtime

ex: 
sudo ln -s /usr/share/zoneinfo/Asia/Bangkok /etc/localtime