Linux time zone and time change

Article Title: Linux time zone and time change. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.

Linux Clock is divided into System Clock and Real Time Clock (RTC. The system clock is the current Linux Kernel clock, and the hardware clock is the battery-powered clock on the motherboard. This hardware clock can be set in the BIOS. When Linux is started, the hardware clock reads the system clock settings, and then the system clock runs independently of the hardware.

All commands (including functions) in Linux use the system clock settings. In Linux, the commands used for clock viewing and setting mainly include date, hwclock, and clock. Among them, clock and hwclock use similar, just use one line, but clock commands not only support x86 hardware system, but also support Alpha hardware system.
　　
1. date
　　
View system time
　　
# Date
　　
Set system time
　　
# Date -- set "07/07/06" (month/day/year hour: minute: second)
　　
2. hwclock/clock
　　
View hardware time
　　
# Hwclock -- show
　　
Or # clock -- show
　　
Set hardware time
　　
# Hwclock -- set -- date = "07/07/06" (month/day/year hour: minute: second)
　　
Or # clock -- set -- date = "07/07/06" (month/day/year hour: minute: second)
　　
3. Hardware time and System Time Synchronization
　　
As mentioned earlier, when the system is restarted, the hardware time reads the system time for synchronization. However, if the system time is not restarted, you need to use the hwclock or clock command to synchronize data.
　　
Hardware clock and system clock synchronization: # hwclock -- hctosys (hc indicates hardware time, sys indicates system time) or # clock -- hctosys
　　
System clock and hardware clock synchronization: # hwclock -- systohc or # clock -- systohc
　　
4. Time Zone settings
　　
# Tzselect
　　
Please identify a location so that time zone rules can be set correctly. Please select a continent or ocean

1) Africa

2) Americas

3) Antarctica

4) Arctic Ocean

5) Asia

6) Atlantic Ocean

7) Australia

8) Europe

9) Indian Ocean

10) Pacific Ocean

11) none-I want to specify the time zone using the Posix TZ format.

Input 5, Asia
　　
Please select a country

1) Afghanistan

18) Israel

35) Palestine

2) armenia

19) Japan

36) Philippines

3) Azerbaijan

20) Jordan

37) Qatar

4) Bahrain

21) Kazakhstan

38) Russia

5) Bangladesh

22) Korea (North)

39) Saudi Arabia

6) Bhutan

23) Korea (South)

40) Singapore

7) Brunei

24) Kuwait

41) Sri Lanka

8) Cambodia

25) Kyrgyzstan

42) Syria

9) China

26) Laos

43) Taiwan

10) Cyprus

27) Lebanon

44) Tajikistan

11) East Timor

28) Macau

45) Thailand

12) Georgia

29) Malaysia

46) Turkmenistan

13) Hong Kong

30) Julia

47) United Arab Emirates

14) India

31) Myanmar (Burma)

48) Uzbekistan

15) Indonesia

32) Nepal

49) Vietnam

16) Iran

33) Oman

50) Yemen

17) Iraq

34) Pakistan

Enter 9, China
　　
Please select one of the following time zone regions

1) east China-Beijing, Guangdong, Shanghai, etc.

2) Heilongjiang

3) central China-Gansu, Guizhou, Sichuan, Yunnan, etc.

4) Tibet & most of Xinjiang Uyghur

5) southwest Xinjiang Uyghur

Enter 1, Beijing time
　　
The following information has been given:
　　
China east China-Beijing, Guangdong, Shanghai, etc
　　
Therefore TZ = "Asia/Shanghai" will be used. Local time is now: Fri Jul 7 10:32:18 CST 2006. Universal Time is now: Fri Jul 7 02:32:18 UTC 2006.Is the above information OK? 1) Yes2) No

Enter 1, OK
　　
If you do not need the tzselect command, you can modify the time zone of the file.
　　
# Vi/etc/sysconfig/clock ZONE = Asia/Shanghai (Query files under/usr/share/zoneinfo) UTC = false ARC = false
　　
# Rm/etc/localtime
　　
# Ln-sf/usr/share/zoneinfo/Asia/Shanghai/etc/localtime
　
Restart.