xref: /freebsd/contrib/tzdata/README (revision 6829dae12bb055451fa467da4589c43bd03b1e64)
1README for the tz distribution
2
3"What time is it?" -- Richard Deacon as The King
4"Any time you want it to be." -- Frank Baxter as The Scientist
5					(from the Bell System film "About Time")
6
7The Time Zone Database (called tz, tzdb or zoneinfo) contains code and
8data that represent the history of local time for many representative
9locations around the globe.  It is updated periodically to reflect
10changes made by political bodies to time zone boundaries, UTC offsets,
11and daylight-saving rules.
12
13See <https://www.iana.org/time-zones/repository/tz-link.html> or the
14file tz-link.html for how to acquire the code and data.  Once acquired,
15read the comments in the file 'Makefile' and make any changes needed
16to make things right for your system, especially if you are using some
17platform other than GNU/Linux.  Then run the following commands,
18substituting your desired installation directory for "$HOME/tzdir":
19
20	make TOPDIR=$HOME/tzdir install
21	$HOME/tzdir/usr/bin/zdump -v America/Los_Angeles
22
23This database of historical local time information has several goals:
24
25 * Provide a compendium of data about the history of civil time that
26   is useful even if not 100% accurate.
27
28 * Give an idea of the variety of local time rules that have existed
29   in the past and thus may be expected in the future.
30
31 * Test the generality of the local time rule description system.
32
33The information in the time zone data files is by no means authoritative;
34fixes and enhancements are welcome.  Please see the file CONTRIBUTING
35for details.
36
37Thanks to these Time Zone Caballeros who've made major contributions to the
38time conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz;
39Guy Harris; Mark Horton; John Mackin; and Bradley White.  Thanks also to
40Michael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales
41for testing work, and to Gwillim Law for checking local mean time data.
42Thanks in particular to Arthur David Olson, the project's founder and first
43maintainer, to whom the time zone community owes the greatest debt of all.
44None of them are responsible for remaining errors.
45
46-----
47
48This file is in the public domain, so clarified as of 2009-05-17 by
49Arthur David Olson.  The other files in this distribution are either
50public domain or BSD licensed; see the file LICENSE for details.
51