linux时区和时间设置

1，修改时区

调整时区使用tzselect

[root@lyn ~]# hwclock

Tue 13 Nov 2018 11:52:26 PM AST  -0.198205 seconds

[root@lyn ~]# 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.

#? 5

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) Mongolia              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

#? 9

Please select one of the following time zone regions.

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

2) Heilongjiang (except Mohe), Jilin

3) central China - Sichuan, Yunnan, Guangxi, Shaanxi, Guizhou, etc.

4) most of Tibet & Xinjiang

5) west Tibet & Xinjiang

#? 1 

The following information has been given: 

        China

        east China - Beijing, Guangdong, Shanghai, etc.

Therefore TZ='Asia/Shanghai' will be used.

Local time is now:      Wed Nov 14 11:52:47 CST 2018.

Universal Time is now:  Wed Nov 14 03:52:47 UTC 2018.

Is the above information OK?

1) Yes

2) No

#? 1

 You can make this change permanent for yourself by appending the line

        TZ='Asia/Shanghai'; export TZ

to the file '.profile' in your home directory; then log out and log in again.

Here is that TZ value again, this time on standard output so that you

can use the /usr/bin/tzselect command in shell scripts:

Asia/Shanghai

注：修改profile文件，添加以下两行：

TZ='Asia/Shanghai'

export TZ

[root@lyn ~]# vim /etc/profile

[root@lyn ~]# source /etc/profile

[root@lyn ~]# date

Wed Nov 14 11:56:16 CST 2018

由此发现，时区由AST 变成了CST。CST ：中国标准时间

2，修改时间

注：linux系统启动时，系统时间同步硬件时间，如果只修改系统时间，重启后系统时间就会变成硬件时间。

例如，现在要求设置系统时间为2018-11-14 10:45:35

1，使用date查看系统时间。

[root@lyn ~]# date

Wed Nov 14 18:29:43 CST 2018

2，查看硬件时间，使用命令hwclock。

[root@lyn ~]# hwclock

Wed 14 Nov 2018 06:29:41 PM CST  -0.557725 seconds

3，调整时间为要求的时间。

方法一：先设置系统时间，再根据系统时间同步硬件时间。

[root@lyn ~]# date -s 11/14/2018

Wed Nov 14 00:00:00 CST 2018

[root@lyn ~]# date -s 10:48:50

Wed Nov 14 10:48:50 CST 2018

[root@lyn ~]# hwclock --systohc  ##使用系统时间同步硬件时间

[root@lyn ~]# hwclock

Wed 14 Nov 2018 10:49:33 AM CST  -0.756860 seconds

方法二：先设置硬件时间，再根据硬件时间同步系统时间，或者重启系统。

[root@lyn ~]# hwclock --set --date="11/14/2018 10:56:35"

[root@lyn ~]# hwclock

Wed 14 Nov 2018 10:56:44 AM CST  -0.709765 seconds

[root@lyn ~]# hwclock --hctosys  ##使用硬件时间同步系统时间

[root@lyn ~]# date

Wed Nov 14 10:57:11 CST 2018