1 .\" Copyright (c) 1996 Wolfram Schneider <wosch@FreeBSD.org>. Berlin.
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31 .Nd set local timezone
39 utility reads a database of timezone information and presents a menu
40 allowing the user to select a specific zone without knowing the details
41 of the database layout.
42 The selected zone is installed as the system
46 utility also determines whether any adjustment is necessary for systems where
47 the hardware clock does not keep
50 The following option is available:
51 .Bl -tag -offset indent -width Fl
53 Do not create or copy files.
56 It is possible to short-circuit the menu system by specifying a
58 on the command line; this is intended mainly for pre-configured
61 The contents of the timezone database are indexed by
62 .Pa /usr/share/zoneinfo/zone.tab .
63 This file lists, for each timezone data file, the
65 3166 territory code, approximate geographical coordinates
69 and location within the territory.
71 The maintainers of the database maintain the following policies:
72 .Bl -enum -offset indent
74 At least one zone for every country or inhabited geographical territory.
76 One zone for every distinct, documented timezone history since the
79 epoch (January 1, 1970,
82 Each zone is named for the most populous city therein.
84 the database includes pre-1970 history for its city.)
86 The source code to the database
87 .Pq Pa /usr/src/share/zoneinfo/[a-z]*
88 contains many additional comments and documentation references for the
91 .Bl -tag -width /usr/share/zoneinfo/zone.tab -compact
93 current time zone file
94 .It Pa /etc/wall_cmos_clock
97 .It Pa /usr/share/misc/iso3166
100 3166 territory codes to names
101 .It Pa /usr/share/zoneinfo
102 directory for zoneinfo files
103 .It Pa /usr/share/zoneinfo/zone.tab
104 mapping of timezone file to country and location
116 The representation of certain localities as being associated with certain
117 countries and/or territories is for the purposes of identification only,
118 and does not imply any endorsement or rejection on the part of the
120 Project of the territorial claims of any entity.
122 Programs which are already running when
126 will not reflect the updated timezone.
127 When the system is first configured for a
129 hardware clock, it is necessary to run
131 (which normally happens as a part of system startup) in order to update
132 the kernel's idea of the correct timezone offset.