NAME

tzdialog — set local timezone

SYNOPSIS

DESCRIPTION

The tzdialog utility reads a database of timezone information and presents a menu allowing the user to select a specific zone without knowing the details of the database layout. The selected zone is installed as the system default zone. The tzdialog utility also determines whether any adjustment is necessary for systems where the hardware clock does not keep UTC.

The following option is available:

It is possible to short-circuit the menu system by specifying the location of a zoneinfo_file or the name of the zoneinfo_name on the command line; this is intended mainly for pre-configured installation scripts or people who know which zoneinfo they want to install.

TIMEZONE DATABASE

The contents of the timezone database are indexed by /usr/share/zoneinfo/zone.tab. This file lists, for each timezone data file, the ISO 3166 territory code, approximate geographical coordinates (in ISO 6709 format), and location within the territory.

The maintainers of the database maintain the following policies:

1. At least one zone for every country or inhabited geographical territory.
2. One zone for every distinct, documented timezone history since the beginning of the UNIX epoch (January 1, 1970, GMT).
3. Each zone is named for the most populous city therein. (Where possible, the database includes pre-1970 history for its city.)

The source code to the database (/usr/src/share/zoneinfo/[a-z]*) contains many additional comments and documentation references for the historically minded.

DEPENDENCIES

The following standard commands are required by tzdialog:

awk(1), cat(1), dialog(1), grep(1), id(1), ln(1), printf(1), rm(1), sort(1), strings(1), stty(1), uname(1), which(1)

The following standard commands are optional, based on arguments passed and situation, but enhance the abilities of tzdialog:

Xdialog(1)

FILES

/etc/localtime

current time zone file

/etc/wall_cmos_clock

see adjkerntz(8)

/usr/share/misc/iso3166

mapping of ISO 3166 territory codes to names

/usr/share/zoneinfo

directory for zoneinfo files

/usr/share/zoneinfo/zone.tab

mapping of timezone file to country and location

/var/db/zoneinfo

saved name of the timezone file installed last

EXAMPLES

Normal usage, to select the right zoneinfo file via the dialog-based user interface:

Install the file /usr/share/zoneinfo/Australia/Sydney:

Install the zoneinfo file for Australia/Sydney, assumed to be located in /usr/share/zoneinfo:

Reinstall last installed zoneinfo file (as specified in /var/db/zoneinfo):

SEE ALSO

date(1), adjtime(2), ctime(3), timezone(3), tzfile(5), adjkerntz(8), zdump(8), zic(8)

DISCLAIMER

The representation of certain localities as being associated with certain countries and/or territories is for the purposes of identification only, and does not imply any endorsement or rejection on the part of the FreeBSD Project of the territorial claims of any entity.

BUGS

Programs which are already running when tzdialog creates or updates /etc/localtime will not reflect the updated timezone. When the system is first configured for a non-UTC hardware clock, it is necessary to run adjkerntz(8) (which normally happens as a part of system startup) in order to update the kernel's idea of the correct timezone offset.

AUTHORS

Devin E. Teske.