Setting timezone for Debian/Linux

I am trying to set timezone to utc+10 but can’t work out the correct command. I thought: hwclock -systohc --utc+10:00 but it doesn’t work.
Any suggestions? Ta

I got it:
1: Remove link to /etc/localtime

Example:

ls -l /etc/localtime

-rw-r–r–. 3 root root 183 Nov 12 2015 /etc/localtime

unlink /etc/localtime

2: Check where the Sydney related time is in /usr/share/zoneinfo folder.
and link to /etc/localtime

ln -s /usr/share/zoneinfo/Australia/Sydney /etc/localtime

Then by entering date again, you get:
Thu Jul 23 13:08:44 AEST 2015
which is correct timezone
Voila

or simply run:

# dpkg-reconfigure tzdata

and choose your desired timezone from the menu.

hope it helps

Lubos