Changing the timezone on a RHEL5/CentOS system

How do I change the timezone on a RHEL5 system? I'm reading the instructions here - http://www.cyberciti.biz/faq/howto-linux-unix-change-setup-timezone-tz-variable/

But they seem very bold (altering the /etc/localtime file).

Is this an acceptable practice (steps from link below):

Generic procedure to change timezone
Change directory to /etc
# cd /etc
Create a symlink to file localtime:
# ln -sf /usr/share/zoneinfo/EST localtime

Solution 1:

Yes, this is exactly what I did to an RHEL5 box two days ago, and it worked fine (with the difference that I hard-linked the file, not soft-linked, but I don't see there should be much difference).

If there is already a localtime file in place it is perhaps best to move the old one aside and put the new one in place in one operation:

cd /etc; mv localtime localtime.orig; ln /usr/share/zoneinfo/EST localtime

Solution 2:

It works, but the traditional RedHat way is to use a system-config-* utility. In this case, it'd be system-config-time.

timeconfig also does the job.

Solution 3:

I've been using the symlink method for years, but that's the wrong way. Because when the tzdata package gets updated the symlink gets blown away. Instead:

1. set the wanted zone in the file /etc/sysconfig/clock where the zone= value is the filename for the zone you want from /usr/share/zoneinfo, but without that full path. For instance: zone="America/Chicago"

2. rm /etc/localtime

3. cp /usr/share/zoneinfo/America/Chicago /etc/localtime

   using Chicago is just an example.

4. date