xref: /freebsd/usr.sbin/tzsetup/tzsetup.8 (revision 4f0ff49fee00dee624e13b2d305cf9dfee395b7d)
1.\" Copyright (c) 1996 Wolfram Schneider <wosch@FreeBSD.org>. Berlin.
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25.Dd June 14, 2024
26.Dt TZSETUP 8
27.Os
28.Sh NAME
29.Nm tzsetup
30.Nd set local timezone
31.Sh SYNOPSIS
32.Nm
33.Op Fl nrs
34.Op Fl C Ar chroot_directory
35.Op Ar zoneinfo_file | zoneinfo_name
36.Sh DESCRIPTION
37The
38.Nm
39utility reads a database of timezone information and presents a menu
40allowing the user to select a specific zone without knowing the details
41of the database layout.
42The selected zone is installed as the system
43default zone.
44The
45.Nm
46utility also determines whether any adjustment is necessary for systems where
47the hardware clock does not keep UTC.
48.Pp
49The following options are available:
50.Bl -tag -offset indent -width Fl
51.It Fl C Ar chroot_directory
52Open all files and directories relative to
53.Ar chroot_directory .
54.It Fl n
55Do not create or symlink files.
56.It Fl r
57Reinstall the zoneinfo file installed last time.
58The name is obtained from
59.Pa /var/db/zoneinfo .
60.It Fl s
61Skip the initial question about adjusting the clock if not set to UTC.
62.Nm
63will neither create nor delete
64.Pa /etc/wall_cmos_clock .
65On a newly installed system, the hardware clock will keep UTC.
66This option is enabled automatically on non-x86 hardware.
67.El
68.Pp
69It is possible to short-circuit the menu system by specifying the
70location of a
71.Ar zoneinfo_file
72or the name of the
73.Ar zoneinfo_name
74on the command line; this is intended mainly for pre-configured installation
75scripts or people who know which zoneinfo they want to install.
76.Sh TIMEZONE DATABASE
77The contents of the timezone database are indexed by
78.Pa /usr/share/zoneinfo/zone1970.tab .
79This file lists, for each timezone data file, the ISO 3166 territory code,
80approximate geographical coordinates (in ISO 6709 format),
81and location within the territory.
82.Pp
83The maintainers of the database maintain the following policies:
84.Bl -enum -offset indent
85.It
86At least one zone for every country or inhabited geographical territory.
87.It
88One zone for every distinct, documented timezone history since the
89beginning of the
90.Ux
91epoch (January 1, 1970, GMT).
92.It
93Each zone is named for the most populous city therein.
94(Where possible,
95the database includes pre-1970 history for its city.)
96.El
97.Pp
98The source code to the database
99.Pq Pa /usr/src/contrib/tzdata/[a-z]*
100contains many additional comments and documentation references for the
101historically minded.
102.Sh FILES
103.Bl -tag -width ".Pa /usr/share/zoneinfo/zone1970.tab" -compact
104.It Pa /etc/localtime
105current time zone file
106.It Pa /etc/wall_cmos_clock
107see
108.Xr adjkerntz 8
109.It Pa /usr/share/misc/iso3166
110mapping of ISO 3166 territory codes to names
111.It Pa /usr/share/zoneinfo
112directory for zoneinfo files
113.It Pa /usr/share/zoneinfo/zone1970.tab
114mapping of timezone file to country and location
115.It Pa /var/db/zoneinfo
116saved name of the timezone file installed last
117.El
118.Sh EXAMPLES
119Normal usage, to select the right zoneinfo file via the dialog-based
120user interface:
121.Pp
122.Dl # tzsetup
123.Pp
124Install the file
125.Pa /usr/share/zoneinfo/Australia/Sydney :
126.Pp
127.Dl "# tzsetup /usr/share/zoneinfo/Australia/Sydney"
128.Pp
129Install the zoneinfo file for Australia/Sydney, assumed to be located in
130.Pa /usr/share/zoneinfo :
131.Pp
132.Dl "# tzsetup Australia/Sydney"
133.Pp
134After a reinstall of the zoneinfo files, you can reinstall the
135latest installed zoneinfo file (as specified in
136.Pa /var/db/zoneinfo ) :
137.Pp
138.Dl "# tzsetup -r"
139.Sh SEE ALSO
140.Xr date 1 ,
141.Xr adjtime 2 ,
142.Xr ctime 3 ,
143.Xr timezone 3 ,
144.Xr tzfile 5 ,
145.Xr adjkerntz 8 ,
146.Xr zdump 8 ,
147.Xr zic 8
148.Sh DISCLAIMER
149The representation of certain localities as being associated with certain
150countries and/or territories is for the purposes of identification only,
151and does not imply any endorsement or rejection on the part of the
152.Fx
153Project of the territorial claims of any entity.
154.Sh BUGS
155Programs which are already running when
156.Nm
157creates or updates
158.Pa /etc/localtime
159will not reflect the updated timezone.
160When the system is first configured for a non-UTC
161hardware clock, it is necessary to run
162.Xr adjkerntz 8
163(which normally happens as a part of system startup) in order to update
164the kernel's idea of the correct timezone offset.
165