Daylight Saving Time

[Marcel Garcia Will]

Hi,
someone could help me configuring the SDT?
I´m in Brazil and I have edited the following files:
/usr/share/lib/timezone/timezone.db
/usr/share/lib/timezone/dst.db
where I have created some information for our timezone info.
I need to configure when DST will chang

[Ralf Puchner]

with the tool "timezone" you can simply change the current timezone if sysV applications are used. Why is there any need to edit the timezone-database directly?

[Joris Denayer]

In the tzset manpage, you see:

Setting Time Zone Information

The /etc/zoneinfo/localtime link can be changed by the system administrator
to any file in the /etc/zoneinfo directory.

For example, the following command changes the local time zone to be con-
sistent with the city of New York on the American continent:

# ln -sf /etc/zoneinfo/America/New_York /etc/zoneinfo/localtime


Now, in /etc/zoneinfo/Brazil, you'll find following tzfile-formatted files.
Acre DeNoronha East West

So, following command should do the job.
# ln -sf sf /etc/zoneinfo/Brazil/Acre /etc/zoneinfo/localtime

Of course, you should select the correct file in /etc/zoneinfo/Brazil.

[Ralf Puchner]

Joris,

why not using the supported tool "timezone"?
the changes depend on customer needs it is much simpler and there is no error-potential action necessary.

[Joris Denayer]

FYI

This comes from the timezone sources (/etc/zoneinfo/sources/southamerica). It is like reading a History course.

# Earlier editions of these tables also used the North American style
# for time zones in Brazil, but this was incorrect, as Brazilians say
# "summer time". Reinaldo Goulart, a Sao Paulo businessman active in
# the railroad sector, writes (1999-07-06):
# The subject of time zones is currently a matter of discussion/debate in
# Brazil. Let's say that "the Brasilia time" is considered the
# "official time" because Brasilia is the capital city.
# The other three time zones are called "Brasilia time "minus one" or
# "plus one" or "plus two". As far as I know there is no such
# name/designation as "Eastern Time" or "Central Time".
# So I invented the following (English-language) abbreviations for now.
# Corrections are welcome!
# std dst
# -2:00 FNT FNST Fernando de Noronha
# -3:00 BRT BRST Brasilia
# -4:00 AMT AMST Amazon
# -5:00 ACT ACST Acre


and there is even more




# Brazil

# From Paul Eggert (1993-11-18):
# The mayor of Rio recently attempted to change the time zone rules
# just in his city, in order to leave more summer time for the tourist trade.
# The rule change lasted only part of the day;
# the federal government refused to follow the city's rules, and business
# was in a chaos, so the mayor backed down that afternoon.

# From IATA SSIM (1996-02):
# _Only_ the following states in BR1 observe DST: Rio Grande do Sul (RS),
# Santa Catarina (SC), Parana (PR), Sao Paulo (SP), Rio de Janeiro (RJ),
# Espirito Santo (ES), Minas Gerais (MG), Bahia (BA), Goias (GO),
# Distrito Federal (DF), Tocantins (TO), Sergipe [SE] and Alagoas [AL].
# [The last three states are new to this issue of the IATA SSIM.]

# From Gwillim Law (1996-10-07):
# Geography, history (Tocantins was part of Goias until 1989), and other
# sources of time zone information lead me to believe that AL, SE, and TO were
# always in BR1, and so the only change was whether or not they observed DST....
# The earliest issue of the SSIM I have is 2/91. Each issue from then until
# 9/95 says that DST is observed only in the ten states I quoted from 9/95,
# along with Mato Grosso (MT) and Mato Grosso do Sul (MS), which are in BR2
# (UTC-4).... The other two time zones given for Brazil are BR3, which is
# UTC-5, no DST, and applies only in the state of Acre (AC); and BR4, which is
# UTC-2, and applies to Fernando de Noronha (formerly FN, but I believe it's
# become part of the state of Pernambuco). The boundary between BR1 and BR2
# has never been clearly stated. They've simply been called East and West.
# However, some conclusions can be drawn from another IATA manual: the Airline
# Coding Directory, which lists close to 400 airports in Brazil. For each
# airport it gives a time zone which is coded to the SSIM. From that
# information, I'm led to conclude that the states of Amapa (AP), Ceara (CE),
# Maranhao (MA), Paraiba (PR), Pernambuco (PE), Piaui (PI), and Rio Grande do
# Norte (RN), and the eastern part of Para (PA) are all in BR1 without DST.

# From Marcos Tadeu (1998-09-27):
#
# Brazilian official page
#

# From Jesper Norgaard (2000-11-03):
# [For an official list of which regions in Brazil use which time zones, see:]
# http://pcdsh01.on.br/Fusbr.htm
# http://pcdsh01.on.br/Fusbrhv.htm

# From Paul Eggert (2000-10-02):
# The official decrees referenced below are taken from
#
# Decretos sobre o Horario de Verao no Brasil
# (1999-10-04, in Portuguese).
# The official site for all decrees, including those not related to time, is
#
# Presidencia da Republica, Subchefia para Assuntos Juridicos, Decretos
# (in Portuguese).

# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
# Decree 20,466 (1931-10-01)
# Decree 21,896 (1932-01-10)
Rule Brazil 1931 only - Oct 3 11:00 1:00 S
Rule Brazil 1932 1933 - Apr 1 0:00 0 -
Rule Brazil 1932 only - Oct 3 0:00 1:00 S
# Decree 23,195 (1933-10-10)
# revoked DST.
# Decree 27,496 (1949-11-24)
# Decree 27,998 (1950-04-13)
Rule Brazil 1949 1952 - Dec 1 0:00 1:00 S
Rule Brazil 1950 only - Apr 16 1:00 0 -
Rule Brazil 1951 1952 - Apr 1 0:00 0 -
# Decree 32,308 (1953-02-24)
Rule Brazil 1953 only - Mar 1 0:00 0 -
# Decree 34,724 (1953-11-30)
# revoked DST.
# Decree 52,700 (1963-10-18)
# established DST from 1963-10-23 00:00 to 1964-02-29 00:00
# in SP, RJ, GB, MG, ES, due to the prolongation of the drought.
# Decree 53,071 (1963-12-03)
# extended the above decree to all of the national territory on 12-09.
Rule Brazil 1963 only - Dec 9 0:00 1:00 S
# Decree 53,604 (1964-02-25)
# extended summer time by one day to 1964-03-01 00:00 (start of school).
Rule Brazil 1964 only - Mar 1 0:00 0 -
# Decree 55,639 (1965-01-27)
Rule Brazil 1965 only - Jan 31 0:00 1:00 S
Rule Brazil 1965 only - Mar 31 0:00 0 -
# Decree 57,303 (1965-11-22)
Rule Brazil 1965 only - Dec 1 0:00 1:00 S
# Decree 57,843 (1966-02-18)
Rule Brazil 1966 1968 - Mar 1 0:00 0 -
Rule Brazil 1966 1967 - Nov 1 0:00 1:00 S
# Decree 63,429 (1968-10-15)
# revoked DST.
# Decree 91,698 (1985-09-27)
Rule Brazil 1985 only - Nov 2 0:00 1:00 S
# Decree 92,310 (1986-01-21)
# Decree 92,463 (1986-03-13)
Rule Brazil 1986 only - Mar 15 0:00 0 -
# Decree 93,316 (1986-10-01)
Rule Brazil 1986 only - Oct 25 0:00 1:00 S
Rule Brazil 1987 only - Feb 14 0:00 0 -
# Decree 94,922 (1987-09-22)
Rule Brazil 1987 only - Oct 25 0:00 1:00 S
Rule Brazil 1988 only - Feb 7 0:00 0 -
# Decree 96,676 (1988-09-12)
# except for the states of AC, AM, PA, RR, RO, and AP (then a territory)
Rule Brazil 1988 only - Oct 16 0:00 1:00 S
Rule Brazil 1989 only - Jan 29 0:00 0 -
# Decree 98,077 (1989-08-21)
# with the same exceptions
Rule Brazil 1989 only - Oct 15 0:00 1:00 S
Rule Brazil 1990 only - Feb 11 0:00 0 -
# Decree 99,530 (1990-09-17)
# adopted by RS, SC, PR, SP, RJ, ES, MG, GO, MS, DF.
# Decree 99,629 (1990-10-19) adds BA, MT.
Rule Brazil 1990 only - Oct 21 0:00 1:00 S
Rule Brazil 1991 only - Feb 17 0:00 0 -
# Unnumbered decree (1991-09-25)
# adopted by RS, SC, PR, SP, RJ, ES, MG, BA, GO, MT, MS, DF.
Rule Brazil 1991 only - Oct 20 0:00 1:00 S
Rule Brazil 1992 only - Feb 9 0:00 0 -
# Unnumbered decree (1992-10-16)
# adopted by same states.
Rule Brazil 1992 only - Oct 25 0:00 1:00 S
Rule Brazil 1993 only - Jan 31 0:00 0 -
# Decree 942 (1993-09-28)
# adopted by same states, plus AM.
# Decree 1,252 (1994-09-22)
# adopted by same states, minus AM.
# Decree 1,636 (1995-09-14)
# adopted by same states, plus TO.
# Decree 1,674 (1995-10-13)
# adds AL, SE.
Rule Brazil 1993 1995 - Oct Sun>=11 0:00 1:00 S
Rule Brazil 1994 1995 - Feb Sun>=15 0:00 0 -
Rule Brazil 1996 only - Feb 11 0:00 0 -
# Decree 2,000 (1996-09-04)
# adopted by same states, minus AL, SE.
Rule Brazil 1996 only - Oct 6 0:00 1:00 S
Rule Brazil 1997 only - Feb 16 0:00 0 -
# From Daniel C. Sobral (1998-02-12):
# In 1997, the DS began on October 6. The stated reason was that
# because international television networks ignored Brazil's policy on DS,
# they bought the wrong times on satellite for coverage of Pope's visit.
# This year, the ending date of DS was postponed to March 1
# to help dealing with the shortages of electric power.
#
# From Paul Eggert (1998-02-25):
#
# Brazil Prepares for Papal Visit
# ,
# Church Net UK (1997-10-02).
#
# Decree 2,317 (1997-09-04), adopted by same states.
Rule Brazil 1997 only - Oct 6 0:00 1:00 S
# Decree 2,495
# (1998-02-10)
Rule Brazil 1998 only - Mar 1 0:00 0 -
# Decree 2,780 (1998-09-11)
# adopted by the same states as before.
Rule Brazil 1998 only - Oct 11 0:00 1:00 S
Rule Brazil 1999 only - Feb 21 0:00 0 -
# Decree 3,150
# (1999-08-23) adopted by same states.
# Decree 3,188 (1999-09-30)
# adds SE, AL, PB, PE, RN, CE, PI, MA and RR.
Rule Brazil 1999 only - Oct 3 0:00 1:00 S
Rule Brazil 2000 only - Feb 27 0:00 0 -
# Decree 3,592 (2000-09-06)
# adopted by the same states as before.
# Decree 3,630 (2000-10-13)
# repeals DST in PE and RR, effective 2000-10-15 00:00.
# Decree 3,632 (2000-10-17)
# repeals DST in SE, AL, PB, RN, CE, PI and MA, effective 2000-10-22 00:00.
#
# These give only one year's rules. After that, the rules are guesses
# and are quite possibly wrong, but are more likely than no DST at all.
Rule Brazil 2000 max - Oct Sun>=8 0:00 1:00 S
Rule Brazil 2001 max - Feb Sun>=15 0:00 0 -


# Zone NAME GMTOFF RULES FORMAT [UNTIL]
#
# Atlantic islands: Fernando de Noronha, Trindade, Martin Vaz,
# Atol das Rocas, and Penedos de Sao Pedro e Sao Paulo
Zone America/Noronha -2:09:40 - LMT 1914
-2:00 Brazil FN%sT 1990 Sep 17
-2:00 - FNT
#
# Amapa (AP), east Para (PA)
# East Para includes Belem, Maraba, Serra Norte, and Sao Felix do Xingu.
Zone America/Belem -3:13:56 - LMT 1914
-3:00 Brazil BR%sT 1988 Sep 12
-3:00 - BRT
#
# Maranhao (MA), Piaui (PI), Ceara (CE), Rio Grande do Norte (RN),
# Paraiba (PB)
Zone America/Fortaleza -2:34:00 - LMT 1914
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 - BRT 1999 Sep 30
-3:00 Brazil BR%sT 2000 Oct 22
-3:00 - BRT
#
# Pernambuco (PE) (except Atlantic islands)
Zone America/Recife -2:19:36 - LMT 1914
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 - BRT 1999 Sep 30
-3:00 Brazil BR%sT 2000 Oct 15
-3:00 - BRT
#
# Tocantins (TO)
Zone America/Araguaina -3:12:48 - LMT 1914
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 - BRT 1995 Sep 14
-3:00 Brazil BR%sT
#
# Alagoas (AL), Sergipe (SE)
Zone America/Maceio -2:22:52 - LMT 1914
-3:00 Brazil BR%sT 1990 Sep 17
-3:00 - BRT 1995 Oct 13
-3:00 Brazil BR%sT 1996 Sep 4
-3:00 - BRT 1999 Sep 30
-3:00 Brazil BR%sT 2000 Oct 22
-3:00 - BRT
#
# Bahia (BA), Goias (GO), Distrito Federal (DF), Minas Gerais (MG),
# Espirito Santo (ES), Rio de Janeiro (RJ), Sao Paulo (SP), Parana (PR),
# Santa Catarina (SC), Rio Grande do Sul (RS)
Zone America/Sao_Paulo -3:06:28 - LMT 1914
-3:00 Brazil BR%sT 1963 Oct 23 00:00
-3:00 1:00 BRST 1964
-3:00 Brazil BR%sT
#
# Mato Grosso, Mato Grosso do Sul
Zone America/Cuiaba -3:44:20 - LMT 1914
-4:00 Brazil AM%sT
#
# west Para (PA), Rondonia (RO)
# West Para includes Altamira, Oribidos, Prainha, Oriximina, and Santarem.
Zone America/Porto_Velho -4:15:36 - LMT 1914
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 - AMT
#
# Roraima (RR)
Zone America/Boa_Vista -4:02:40 - LMT 1914
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 - AMT 1999 Sep 30
-4:00 Brazil AM%sT 2000 Oct 15
-4:00 - AMT
#
# east Amazonas (AM): Boca do Acre, Jutai, Manaus, Floriano Peixoto
Zone America/Manaus -4:00:04 - LMT 1914
-4:00 Brazil AM%sT 1988 Sep 12
-4:00 - AMT 1993 Sep 28
-4:00 Brazil AM%sT 1994 Sep 22
-4:00 - AMT
#
# west Amazonas (AM): Atalaia do Norte, Boca do Maoco, Benjamin Constant,
# Eirunepe, Envira, Ipixuna
Zone America/Eirunepe -4:39:28 - LMT 1914
-5:00 Brazil AC%sT 1988 Sep 12
-5:00 - ACT 1993 Sep 28
-5:00 Brazil AC%sT 1994 Sep 22
-5:00 - ACT
#
# Acre (AC)
# Rio_Branco is too ambiguous, since there's a Rio Branco in Uruguay too.
Zone America/Porto_Acre -4:31:12 - LMT 1914
-5:00 Brazil AC%sT 1988 Sep 12
-5:00 - ACT

[Joris Denayer]

Ralf,

If you run timezone, you'll get following choices. I don't see Brazil or whatever in this list.


# timezone


***** MAIN TIMEZONE MENU *****

----------------------------------------------------------------------------

1) Australia 2) Canada 3) Cuba 4) Egypt
5) GB-Eire 6) GMT 7) WET 8) MET
9) EET 10) Hongkong 11) Iceland 12) Israel
13) Jamaica 14) Japan 15) Mexico 16) PRC
17) Poland 18) ROC 19) ROK 20) Singapore
21) Turkey 22) USA

0) None of the above

----------------------------------------------------------------------------

Select the number above that best describes
your location:

[Ralf Puchner]

Joris,

in this case you simply select GMT and GMT-3 which seems to be the right choice for brasil. GMT is always the base if no other timezone matches.

[Joris Denayer]

OK,

Here is my last update for this subject.
Have a look in http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/V51B_ACRO_DUX/ARH9FETE.PDF
Chapter 3.4

Enjoy