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1$OpenBSD: README,v 1.11 2025/06/23 13:53:11 millert Exp $
2
3README for the tz distribution
4
5"What time is it?" -- Richard Deacon as The King
6"Any time you want it to be." -- Frank Baxter as The Scientist
7 (from the Bell System film "About Time")
8
9The Time Zone Database (often called tz or zoneinfo) contains code and
10data that represent the history of local time for many representative
11locations around the globe. It is updated periodically to reflect
12changes made by political bodies to time zone boundaries, UTC offsets,
13and daylight-saving rules.
14
15Unless otherwise specified, all files in the tz code and data are in
16the public domain, so clarified as of 2009-05-17 by Arthur David Olson.
17The few exceptions are code derived from BSD, which uses the BSD license.
18
19Here is a recipe for acquiring, building, installing, and testing the
20tz distribution on a GNU/Linux or similar host.
21
22 mkdir tz
23 cd tz
24 wget --retr-symlinks 'ftp://ftp.iana.org/tz/tz*-latest.tar.gz'
25 gzip -dc tzcode-latest.tar.gz | tar -xf -
26 gzip -dc tzdata-latest.tar.gz | tar -xf -
27
28Be sure to read the comments in "Makefile" and make any changes needed
29to make things right for your system, especially if you are using some
30platform other than GNU/Linux. Then run the following commands,
31substituting your desired installation directory for "$HOME/tzdir":
32
33 make TOPDIR=$HOME/tzdir install
34 $HOME/tzdir/etc/zdump -v America/Los_Angeles
35
36Historical local time information has been included here to:
37
38* provide a compendium of data about the history of civil time
39 that is useful even if the data are not 100% accurate;
40
41* give an idea of the variety of local time rules that have
42 existed in the past and thus an idea of the variety that may be
43 expected in the future;
44
45* provide a test of the generality of the local time rule description
46 system.
47
48The information in the time zone data files is by no means authoritative;
49the files currently do not even attempt to cover all time stamps before
501970, and there are undoubtedly errors even for time stamps since 1970.
51If you know that the rules are different from those in a file, by all means
52feel free to change a file (and please send the changed version to
53tz@iana.org for use in the future). Europeans take note!
54
55Thanks to these Timezone Caballeros who've made major contributions to the
56time conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz;
57Guy Harris; Mark Horton; John Mackin; and Bradley White. Thanks also to
58Michael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales
59for testing work, and to Gwillim Law for checking local mean time data.
60Thanks in particular to Arthur David Olson, the project's founder and first
61maintainer, to whom the timezone community owes the greatest debt of all.
62None of them are responsible for remaining errors.
63
64Look in <ftp://ftp.iana.org/tz/releases/> for updated versions of these files.
65
66Please send comments or information to tz@iana.org.