Linux (RHEL)修改时区

1.修改配置文件修改为上海时区
vi /etc/sysconfig/clock

ZONE="Asia/Shanghai"

2.创建上海时区的软连接

ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

3.重启机器生效

shutdown -Fr now

4.重启后如果时间仍不对，使用date命令调整时间

--时间调整为2017年6月7号11:29:30
date 060711292017.30

5.确认硬件时间匹配

--读取
hwclock -r
--同步
hwclock -w

注意：
1）时区一般建议在安装系统时就选择正确，不建议后期更改
2）tzselect可以指导你如何选择正确的时区，但并不会修改时区

tzselect命令示例：

[root@jyrac1 ~]# 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 Jun  7 11:33:55 CST 2017.
Universal Time is now:  Wed Jun  7 03:33:55 UTC 2017.
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
[root@jyrac1 ~]# 

可以看到，最后只是建议你如何设置时区的环境变量。这可以用来单独设置某个用户下的时区。
比如我在oracle用户临时指定了美国纽约的时区(TZ='America/New_York'; export TZ)，时间就会显示美国纽约的时间。

[oracle@jyrac1 ~]$ date
Wed Jun  7 11:44:35 CST 2017
[oracle@jyrac1 ~]$ TZ='America/New_York'; export TZ
[oracle@jyrac1 ~]$ date
Tue Jun  6 23:44:39 EDT 2017