xref: /freebsd/usr.sbin/tzsetup/tzsetup.8 (revision c6030b380469f928c8cae87ed53bcb234cb3486f)

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.Dd June 14, 2024
.Dt TZSETUP 8
.Os
.Sh NAME
.Nm tzsetup
.Nd set local timezone
.Sh SYNOPSIS
.Nm
.Op Fl nrs
.Op Fl C Ar chroot_directory
.Op Ar zoneinfo_file | zoneinfo_name
.Sh DESCRIPTION
The
.Nm
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
.Nm
utility also determines whether any adjustment is necessary for systems where
the hardware clock does not keep UTC.
.Pp
The following options are available:
.Bl -tag -offset indent -width Fl
.It Fl C Ar chroot_directory
Open all files and directories relative to
.Ar chroot_directory .
.It Fl n
Do not create or symlink files.
.It Fl r
Reinstall the zoneinfo file installed last time.
The name is obtained from
.Pa /var/db/zoneinfo .
.It Fl s
Skip the initial question about adjusting the clock if not set to UTC.
.Nm
will neither create nor delete
.Pa /etc/wall_cmos_clock .
On a newly installed system, the hardware clock will keep UTC.
.El
.Pp
It is possible to short-circuit the menu system by specifying the
location of a
.Ar zoneinfo_file
or the name of the
.Ar 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.
.Sh TIMEZONE DATABASE
The contents of the timezone database are indexed by
.Pa /usr/share/zoneinfo/zone1970.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.
.Pp
The maintainers of the database maintain the following policies:
.Bl -enum -offset indent
.It
At least one zone for every country or inhabited geographical territory.
.It
One zone for every distinct, documented timezone history since the
beginning of the
.Ux
epoch (January 1, 1970, GMT).
.It
Each zone is named for the most populous city therein.
(Where possible,
the database includes pre-1970 history for its city.)
.El
.Pp
The source code to the database
.Pq Pa /usr/src/contrib/tzdata/[a-z]*
contains many additional comments and documentation references for the
historically minded.
.Sh FILES
.Bl -tag -width ".Pa /usr/share/zoneinfo/zone1970.tab" -compact
.It Pa /etc/localtime
current time zone file
.It Pa /etc/wall_cmos_clock
see
.Xr adjkerntz 8
.It Pa /usr/share/misc/iso3166
mapping of ISO 3166 territory codes to names
.It Pa /usr/share/zoneinfo
directory for zoneinfo files
.It Pa /usr/share/zoneinfo/zone1970.tab
mapping of timezone file to country and location
.It Pa /var/db/zoneinfo
saved name of the timezone file installed last
.El
.Sh EXAMPLES
Normal usage, to select the right zoneinfo file via the dialog-based
user interface:
.Pp
.Dl # tzsetup
.Pp
Install the file
.Pa /usr/share/zoneinfo/Australia/Sydney :
.Pp
.Dl "# tzsetup /usr/share/zoneinfo/Australia/Sydney"
.Pp
Install the zoneinfo file for Australia/Sydney, assumed to be located in
.Pa /usr/share/zoneinfo :
.Pp
.Dl "# tzsetup Australia/Sydney"
.Pp
After a reinstall of the zoneinfo files, you can reinstall the
latest installed zoneinfo file (as specified in
.Pa /var/db/zoneinfo ) :
.Pp
.Dl "# tzsetup -r"
.Sh SEE ALSO
.Xr date 1 ,
.Xr adjtime 2 ,
.Xr ctime 3 ,
.Xr timezone 3 ,
.Xr tzfile 5 ,
.Xr adjkerntz 8 ,
.Xr zdump 8 ,
.Xr zic 8
.Sh 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
.Fx
Project of the territorial claims of any entity.
.Sh BUGS
Programs which are already running when
.Nm
creates or updates
.Pa /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
.Xr adjkerntz 8
(which normally happens as a part of system startup) in order to update
the kernel's idea of the correct timezone offset.