Ubuntu修改时区，调整正确时间最简单的方法

本地时间正确，但是时区不对：
root@mirror:/home/mirror# tzselect
Please identify a location so that time zone rules can be set correctly.
Please select a continent, ocean, “coord”, or “TZ”.

1. Africa
2. Americas
3. Antarctica
4. Asia
5. Atlantic Ocean
6. Australia
7. Europe
8. Indian Ocean
9. Pacific Ocean
10. coord - I want to use geographical coordinates.
11. TZ - I want to specify the time zone using the Posix TZ format.
    #? 4
    Please select a country whose clocks agree with yours.
12. Afghanistan 18) Israel 35) Palestine
13. Armenia 19) Japan 36) Philippines
14. Azerbaijan 20) Jordan 37) Qatar
15. Bahrain 21) Kazakhstan 38) Russia
16. Bangladesh 22) Korea (North) 39) Saudi Arabia
17. Bhutan 23) Korea (South) 40) Singapore
18. Brunei 24) Kuwait 41) Sri Lanka
19. Cambodia 25) Kyrgyzstan 42) Syria
20. China 26) Laos 43) Taiwan
21. Cyprus 27) Lebanon 44) Tajikistan
22. East Timor 28) Macau 45) Thailand
23. Georgia 29) Malaysia 46) Turkmenistan
24. Hong Kong 30) Mongolia 47) United Arab Emirates
25. India 31) Myanmar (Burma) 48) Uzbekistan
26. Indonesia 32) Nepal 49) Vietnam
27. Iran 33) Oman 50) Yemen
28. Iraq 34) Pakistan
    #? 9
    Please select one of the following time zone regions.
29. Beijing Time
30. Xinjiang Time
    #? 1

The following information has been given:

    China
    Beijing Time

Therefore TZ=‘Asia/Shanghai’ will be used.
Selected time is now: Fri Dec 31 13:40:43 CST 2021.
Universal Time is now: Fri Dec 31 05:40:43 UTC 2021.
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@mirror:/home/mirror:~$ date
Fri Dec 31 05:39:06 UTC 2021

修改完成后，发现时区还是不正确。按网上的方法cp：

cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

root@mirror:/home/mirror# date -R
Fri, 31 Dec 2021 14:01:03 +0800

vi /etc/localtime

发现最大的变化是时区变了
CST0 ---->CST-8

下次直接vi /etc/localtime 修改时区试试。

以上是时间正确，时区不对的处理方法。

如果是本地时间本身就不正确，方法如下：
date -s MM/DD/YY //修改日期
date -s hh:mm:ss //修改时间

在修改时间以后，还要修改硬件CMOS的时间，方法如下：
hwclock --systohc //非常重要，如果没有这一步的话，后面时间还是不准