xref: /dflybsd-src/share/zoneinfo/README (revision b858e488763a543b5dac00dcce4628270967a642)
18eadffdbSSascha WildnerREADME for the tz distribution
28eadffdbSSascha Wildner
35baf8a10SSascha Wildner"Where do I set the hands of the clock?" -- Les Tremayne as The King
45baf8a10SSascha Wildner"Oh that--you can set them any place you want." -- Frank Baxter as The Scientist
580675326SSascha Wildner					(from the Bell System film "About Time")
680675326SSascha Wildner
78cb73418SSascha WildnerThe Time Zone Database (called tz, tzdb or zoneinfo) contains code and
8d1bcb6beSSascha Wildnerdata that represent the history of local time for many representative
9d1bcb6beSSascha Wildnerlocations around the globe.  It is updated periodically to reflect
10d1bcb6beSSascha Wildnerchanges made by political bodies to time zone boundaries, UTC offsets,
11d1bcb6beSSascha Wildnerand daylight-saving rules.
1280675326SSascha Wildner
13bf5e9998SSascha WildnerSee <https://www.iana.org/time-zones/repository/tz-link.html> or the
14a3b9d54dSSascha Wildnerfile tz-link.html for how to acquire the code and data.  Once acquired,
15bf5e9998SSascha Wildnerread the comments in the file 'Makefile' and make any changes needed
1680675326SSascha Wildnerto make things right for your system, especially if you are using some
1780675326SSascha Wildnerplatform other than GNU/Linux.  Then run the following commands,
1880675326SSascha Wildnersubstituting your desired installation directory for "$HOME/tzdir":
1980675326SSascha Wildner
2080675326SSascha Wildner	make TOPDIR=$HOME/tzdir install
21a3b9d54dSSascha Wildner	$HOME/tzdir/usr/bin/zdump -v America/Los_Angeles
2280675326SSascha Wildner
23*b858e488SSascha WildnerSee the file tz-how-to.html for examples of how to read the data files.
24*b858e488SSascha Wildner
258cb73418SSascha WildnerThis database of historical local time information has several goals:
2680675326SSascha Wildner
278cb73418SSascha Wildner * Provide a compendium of data about the history of civil time that
288cb73418SSascha Wildner   is useful even if not 100% accurate.
2980675326SSascha Wildner
308cb73418SSascha Wildner * Give an idea of the variety of local time rules that have existed
318cb73418SSascha Wildner   in the past and thus may be expected in the future.
3280675326SSascha Wildner
338cb73418SSascha Wildner * Test the generality of the local time rule description system.
3480675326SSascha Wildner
3580675326SSascha WildnerThe information in the time zone data files is by no means authoritative;
3648afb8acSSascha Wildnerfixes and enhancements are welcome.  Please see the file CONTRIBUTING
3748afb8acSSascha Wildnerfor details.
3880675326SSascha Wildner
3948afb8acSSascha WildnerThanks to these Time Zone Caballeros who've made major contributions to the
4080675326SSascha Wildnertime conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz;
4180675326SSascha WildnerGuy Harris; Mark Horton; John Mackin; and Bradley White.  Thanks also to
4280675326SSascha WildnerMichael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales
4380675326SSascha Wildnerfor testing work, and to Gwillim Law for checking local mean time data.
44d1bcb6beSSascha WildnerThanks in particular to Arthur David Olson, the project's founder and first
45d1bcb6beSSascha Wildnermaintainer, to whom the time zone community owes the greatest debt of all.
4680675326SSascha WildnerNone of them are responsible for remaining errors.
4780675326SSascha Wildner
48c19fc1ecSSascha Wildner-----
49c19fc1ecSSascha Wildner
50c19fc1ecSSascha WildnerThis file is in the public domain, so clarified as of 2009-05-17 by
51c19fc1ecSSascha WildnerArthur David Olson.  The other files in this distribution are either
52c19fc1ecSSascha Wildnerpublic domain or BSD licensed; see the file LICENSE for details.
53