We look for the default file for that zone
rhel01 # cd /usr/share/zoneinfo
rhel01 # ls
Africa Cuba GMT0 Japan Poland Universal
America EET GMT-0 Kwajalein Portugal US
Antarctica Egypt GMT+0 Libya posix UTC
Arctic Eire Greenwich MET posixrules WET
Asia EST Hongkong Mexico PRC W-SU
Atlantic EST5EDT HST Mideast PST8PDT zone.tab
Australia Etc Iceland MST right Zulu
Brazil Europe Indian MST7MDT ROC
Canada Factory Iran Navajo ROK
CET GB iso3166.tab NZ Singapore
Chile GB-Eire Israel NZ-CHAT Turkey
CST6CDT GMT Jamaica Pacific UCT
rhel01 # cd America
rhel01 # ls
Adak Cuiaba Juneau North_Dakota Swift_Current
Anchorage Curacao Kentucky Ojinaga Tegucigalpa
Anguilla Danmarkshavn Knox_IN Panama Thule
Antigua Dawson Kralendijk Pangnirtung Thunder_Bay
Araguaina Dawson_Creek La_Paz Paramaribo Tijuana
Argentina Denver Lima Phoenix Toronto
Aruba Detroit Los_Angeles Port-au-Prince Tortola
Asuncion Dominica Louisville Porto_Acre Vancouver
Atikokan Edmonton Lower_Princes Port_of_Spain Virgin
Atka Eirunepe Maceio Porto_Velho Whitehorse
Bahia El_Salvador Managua Puerto_Rico Winnipeg
Bahia_Banderas Ensenada Manaus Rainy_River Yakutat
Barbados Fortaleza Marigot Rankin_Inlet Yellowknife
Belem Fort_Wayne Martinique Recife
Belize Glace_Bay Matamoros Regina
Blanc-Sablon Godthab Mazatlan Resolute
Boa_Vista Goose_Bay Mendoza Rio_Branco
Bogota Grand_Turk Menominee Rosario
Boise Grenada Merida Santa_Isabel
Buenos_Aires Guadeloupe Metlakatla Santarem
Cambridge_Bay Guatemala Mexico_City Santiago
Campo_Grande Guayaquil Miquelon Santo_Domingo
Cancun Guyana Moncton Sao_Paulo
Caracas Halifax Monterrey Scoresbysund
Catamarca Havana Montevideo Shiprock
Cayenne Hermosillo Montreal Sitka
Cayman Indiana Montserrat St_Barthelemy
Chicago Indianapolis Nassau St_Johns
Chihuahua Inuvik New_York St_Kitts
Coral_Harbour Iqaluit Nipigon St_Lucia
Cordoba Jamaica Nome St_Thomas
Costa_Rica Jujuy Noronha St_Vincent
rhel01 # ls
Africa Cuba GMT0 Japan Poland Universal
America EET GMT-0 Kwajalein Portugal US
Antarctica Egypt GMT+0 Libya posix UTC
Arctic Eire Greenwich MET posixrules WET
Asia EST Hongkong Mexico PRC W-SU
Atlantic EST5EDT HST Mideast PST8PDT zone.tab
Australia Etc Iceland MST right Zulu
Brazil Europe Indian MST7MDT ROC
Canada Factory Iran Navajo ROK
CET GB iso3166.tab NZ Singapore
Chile GB-Eire Israel NZ-CHAT Turkey
CST6CDT GMT Jamaica Pacific UCT
rhel01 # cd America
rhel01 # ls
Adak Cuiaba Juneau North_Dakota Swift_Current
Anchorage Curacao Kentucky Ojinaga Tegucigalpa
Anguilla Danmarkshavn Knox_IN Panama Thule
Antigua Dawson Kralendijk Pangnirtung Thunder_Bay
Araguaina Dawson_Creek La_Paz Paramaribo Tijuana
Argentina Denver Lima Phoenix Toronto
Aruba Detroit Los_Angeles Port-au-Prince Tortola
Asuncion Dominica Louisville Porto_Acre Vancouver
Atikokan Edmonton Lower_Princes Port_of_Spain Virgin
Atka Eirunepe Maceio Porto_Velho Whitehorse
Bahia El_Salvador Managua Puerto_Rico Winnipeg
Bahia_Banderas Ensenada Manaus Rainy_River Yakutat
Barbados Fortaleza Marigot Rankin_Inlet Yellowknife
Belem Fort_Wayne Martinique Recife
Belize Glace_Bay Matamoros Regina
Blanc-Sablon Godthab Mazatlan Resolute
Boa_Vista Goose_Bay Mendoza Rio_Branco
Bogota Grand_Turk Menominee Rosario
Boise Grenada Merida Santa_Isabel
Buenos_Aires Guadeloupe Metlakatla Santarem
Cambridge_Bay Guatemala Mexico_City Santiago
Campo_Grande Guayaquil Miquelon Santo_Domingo
Cancun Guyana Moncton Sao_Paulo
Caracas Halifax Monterrey Scoresbysund
Catamarca Havana Montevideo Shiprock
Cayenne Hermosillo Montreal Sitka
Cayman Indiana Montserrat St_Barthelemy
Chicago Indianapolis Nassau St_Johns
Chihuahua Inuvik New_York St_Kitts
Coral_Harbour Iqaluit Nipigon St_Lucia
Cordoba Jamaica Nome St_Thomas
Costa_Rica Jujuy Noronha St_Vincent
rhel01 # ls -l Santiago
-rw-r–r–. 2 root root 9227 Oct 19 2011 Santiago
rhel01 #
to change simply copy that file to /etc/localtime
rhel01 # cp /usr/share/zoneinfo/America/Santiago /etc/localtime
once copied, we check it
rhel01 # date Wed Nov 21 07:30:50 CLST 2012 rhel01 #
with that would be enough, but just in case we have applications that use the old format of timezone, so we change the /etc/sysconfig/clock too
rhel01 # cat /etc/sysconfig/clock
ZONE="America/Santiago"
rhel01 #
ZONE="America/Santiago"
rhel01 #
the timezone change is done without reboot the server, just restart applications that use the timezone.