#rm /etc/localtime
#ln -sf /usr/share/zoneinfo/GMT /etc/localtime

#date

#/etc/init.d/syslog restart
#/etc/init.d/crond restart

#rm /etc/localtime
#ln -sf /usr/share/zoneinfo/Asia/Tokyo /etc/localtime

# LANG=C
# date
Tue Mar 10 11:09:43 JST 2015

#/etc/init.d/syslog restart
#/etc/init.d/crond restart

#rm /etc/localtime
#ln -sf /usr/share/zoneinfo/Asia/Hong_Kong /etc/localtime

# date
Tue Mar 10 10:08:54 HKT 2015

#/etc/init.d/syslog restart
#/etc/init.d/crond restart

Hardware             Linux Kernel
  [Interval Timer]----> [System Clock]
                          |    date, ntpdate, ntpd
  [hardware Clock]--------+
      hwclock

#vi /etc/sysconfig/clock

ZONE="Asia/Tokyo"
UTC=false

# source /etc/sysconfig/clock

# cat /etc/adjtime

# cat /etc/sysconfig/clock

#ZONE=""
UTC=true

# source /etc/sysconfig/clock

# cat /etc/adjtime
-0.068450 1422083052 0.000000
1422083052
UTC

• https://www.centos.org/docs/5/html/5.1/Deployment_Guide/s2-sysconfig-clock.html