A WORD OF WARNING
tzsetup - set the local timezone
tzsetup [-y? [-g?
This manual page explains how you can use the tzsetup
utility to set the local timezone. This is necessary to let
your system know about the difference between system time
and local time (the time in the real world). It is also
necessary to make your system behave nicely when your
location uses Daylight Savings Time.
A valid system time together with the correct local time
zone will give you best performance and highest
reliablility. It is especially important in a network
environment, where even small time differences can make a
mirror refetch a whole ftp site, or where time stamps on
external file systems are used.
tzsetup is typically called without any parameters
from the shell. Optionally, the -y parameter can be used, to
make it always change your time zone without asking first.
The -g parameter can also be used, to make it ask if the
hardware clock is set to gmt or not.
After you made your choice, tzsetup will try to
change the timezone for you. See the Internals
section below for technical details. You must have root
privilegies to actually change anything. Please use
tzselect(1)? as a user space command to just look at
the timezones. It will print the local time in any timezone
recognized by the system.
A WORD OF WARNING
What timezone is correct for your system? It depends on the
geographical location of the machine. Getting the correct
location is important, but the system must also know how
your hardware clock is set. Most DOS based PCs set their
hardware clock on Local Time, while most UNIX systems set
their hardware clock to UTC.
The Debian GNU/Linux system gains its knowledge of this
setting from the file /etc/default/rcS. This file
contains either the line UTC=yes, which indicates
that the hardware clock is set to UTC, or it contains the
line UTC=no, which declares the hardware clock is set
to Local Time. If these setting are correct, and the
hardware clock is truely set as indicated, then configuring
the proper timezone for the machine will cause the proper
date and time to be displayed. If these are not set
correctly, the the reported time will be quite incorrect.
See hwclock(8) for more details on this
The work done by tzsetup is actually pretty simple.
It just updates the link /etc/localtime to point to
the correct timezone installed in
There is nothing wrong with doing this manually. However,
using tzsetup you don't have to remember the path to
This program is based on tzconfig(8)? -- the only
major difference is that this program uses debconf for its
user interface, and that it allows configuration of
hwclock(8) tzselect(8) rcS(5)