Changing the time Zone in Linux and AIX

Changing the Time Zone in Linux.

1. Logged in as root, check which timezone your machine is currently using by executing `date`. You'll see something like Mon 17 Jan 2005 12:15:08 PM PST, PST in this case is the current timezone.

2. Change to the directory /usr/share/zoneinfo here you will find a list of time zone regions. Choose the most appropriate region, if you live in Canada or the US this directory is the "America" directory.

3. If you wish, backup the previous timezone configuration by copying it to a different location. Such as

   mv /etc/localtime  /etc/localtime-old

4. Create a symbolic link from the appropiate timezone to /etc/localtime. Example:

   ln -sf /usr/share/zoneinfo/Europe/Amsterdam /etc/localtime

5. If you have the utility rdate, update the current system time by executing

   /usr/bin/rdate -s time-a.nist.gov

6. Set the ZONE entry in the file /etc/sysconfig/clock file (e.g. "America/Los_Angeles")

7. Set the hardware clock by executing:

   /sbin/hwclock --systohc

Tips

• The time server parameter for rdate can be any public server that supports the RFC-868 time protocol. A list of public RFC-868 servers can be found at [2]. Note: As of April 2007, NIST announced it would phase out support for RFC-868 (scroll to the bottom of [3] to see the announcement). This has not happened as of April 2009).

• On some versions of RedHat Linux, Slackware, Gentoo, SuSE, Debian, Ubuntu, and anything else that is "normal", the command to display and change the time is 'date', not 'clock'

• On RedHat Linux there is a utility called "Setup" that allows one to select the timezone from a list, but you must have installed the 'redhat-config-date' package. <>

• On mobile phones and other small devices that run Linux, the time zone is stored differently. It is written in /etc/TZ, in the format that is described, for instance, in [4]. Edit this file manually or use echo (for instance, echo GMT0BST > /etc/TZ to set the the timezone of the United Kingdom).

• To setup UTC :

• vi /etc/sysconfig/clock and change the UTC line to: "UTC=true"

• On systems that use dpkg (for example Debian and Ubuntu/Kubuntu), you should try "sudo dpkg-reconfigure tzdata". This will set up everything correctly in very few, simple steps.

Warnings

Some applications (such as PHP) have separate timezone settings from the system timezone.

• On some systems, there is a system utility provided that will prompt for the correct timezone and make the proper changes to the system configuration. For example, Debian provides the "tzsetup" or "tzconfig" utility.

Changing the Time

To change the time use date followed by the month, day, hour, minute, and year all numeric and no spaces. So, to set the date and time to November 2nd, 2003 12:57

Changing the Time zone in AIX

TO change the Time zone in AIX

1) smitty
2) selce the system environment
3) select the change time
4) select the change the time zone using user defined
6) enter the the time zone and valu Like IST , _5:30

Than you are done with the time zone.
But AIX needs the Reboot .
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