[Linux] 通过指令修改时区 tzselect

修改时区

tzselect 指令只是根据提示一步步选择正确时区，但不能真正修改时区，最后输入提示的指令，然后重启，才能永久修改。

aaron@ubuntu:~$ 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.
 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) Beijing Time
2) Xinjiang Time
#? 1

The following information has been given:

        China
        Beijing Time

Therefore TZ='Asia/Shanghai' will be used.
Local time is now:      Thu May 24 14:37:15 CST 2018.
Universal Time is now:  Thu May 24 06:37:15 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
// 此时时区还没有修改成功
// 根据提示输入 TZ='Asia/Shanghai'; export TZ 但重启后又失效
aaron@ubuntu:~$ date
Wed May 23 23:37:03 PDT 2018
aaron@ubuntu:~$ sudo cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime 
[sudo] password for aaron: 
// 更新时间时，提示没有安装 ntpdate
aaron@ubuntu:~$ sudo ntpdate time.windows.com
sudo: ntpdate: command not found
// 安装
aaron@ubuntu:~$ sudo apt-get install ntpdate
// 更新时间
aaron@ubuntu:~$ sudo ntpdate time.windows.com
24 May 14:39:02 ntpdate[1449]: adjust time server 51.140.127.197 offset 0.044998 sec
aaron@ubuntu:~$ date
Thu May 24 14:38:08 CST 2018
// 重启
aaron@ubuntu:~$ sudo reboot
// 时区设置成功
aaron@ubuntu:~$ date
Thu May 24 14:41:10 CST 2018