to select and set the time zone.
command: tzconfig
(tzconfig copies the right time zone file from /usr/share/zoneinfo to /etc/localtime and puts the name of the timezone into /etc/timezone)
If your system does not have tzconfig, you may use something else.
tzselect
This will provide a set of different time zones to choose. If you would like to set the time to UTC, choose the option which says something like ‘none of the above’, or ‘none of these’ or something to this effect.
Or you can use
sudo dpkg-reconfigure tzdata