How to set timezone from shell quickly
The easiest trick is to override /etc/localtime:# ln -sf /usr/share/zoneinfo/Europe/Prague /etc/localtime
According to the BIOS clocks and BIOS-UTC setting of the OS it is usually good idea to correct time:# date +%T -s "22:30"
It's also quite good idea to start NTP daemon:# service ntpd restart
# chkconfig ntpd on
For Fedora/RHEL systems you should also update sysconfig file to make this permanent:
# echo 'ZONE="Europe/Prague"' > /etc/sysconfig/clock
This is very important if you run a virtual guest since clocks are not very accurate for them.