Time in server is important, because application like web, logging, etc will need time in their process.
Change Time Zone on Ubuntu
1. Open terminal
2. Enter command
dpkg-reconfigure tzdata
3. Follow the instruction
Change Time Zone on Freebsd
1. find your zone info on /usr/share/zoneinfo
2. copy and paste your zone info to /etc/localtime
for example if you live in bangkok
run this command
cp /usr/share/zoneinfo/Asia/Bangkok /etc/localtime