173. timedatectl tzselect¶
173.1. ubuntu tzselect设置过程¶
选择系统所在时区。
有时候服务器在全球各地，虽然安装地点不一样，时区已经自动设置好，但是希望显示的时候按照亚洲时区来显示，好知道什么时间发生了什么事。
查看系统时间，发现是西5区
root@ubuntu:~# date -R
Wed, 13 Feb 2019 03:42:38 -0500
root@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
#? 13
The following information has been given:
Hong Kong
Therefore TZ='Asia/Hong_Kong' will be used.
Selected time is now: Wed Feb 13 16:47:13 HKT 2019.
Universal Time is now: Wed Feb 13 08:47:13 UTC 2019.
Is the above information OK?
1) Yes
2) No
#? 1
You can make this change permanent for yourself by appending the line
TZ='Asia/Hong_Kong'; 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/Hong_Kong
并没有起效果，系统提示，要想永久修改，在~/.profile后面追加一行 TZ='Asia/Hong_Kong'; export TZ 追加之后，退出重新登录或者执行：
source .profile
root@ubuntu:~# date -R
Wed, 13 Feb 2019 16:52:00 +0800
root@ubuntu:~#
发现已经变成了东8区
173.1.1. RedHat timedatectl 设置过程¶
选择时区： 参考[官方手册]
timedatectl list-timezones
timedatectl set-timezone Asia/Shanghai
[root@localhost linux]# timedatectl
Local time: Thu 2019-04-11 16:33:46 CST
Universal time: Thu 2019-04-11 08:33:46 UTC
RTC time: Thu 2019-04-11 08:33:47
Time zone: Asia/Shanghai (CST, +0800)
NTP enabled: yes
NTP synchronized: yes
RTC in local TZ: no
DST active: n/a
[root@localhost linux]#
时间同步chrony。redhat 8.0使用chrony作为NTP客户端使用如下命令查看ntp同步状态
yum install chrony
systemctl status chronyd #查看服务
systemctl enable chronyd #开机启动
systemctl start chronyd #启动服务
chronyc sourcestats #查看同步状态
[root@centos ~]# chronyc sourcestats
210 Number of sources = 4
Name/IP Address NP NR Span Frequency Freq Skew Offset Std Dev
==============================================================================
tock.ntp.infomaniak.ch 1 0 0 +0.000 2000.000 +0ns 4000ms
120.25.115.20 2 0 2 +0.000 2000.000 -10012h 4000ms
ntp5.flashdance.cx 1 0 0 +0.000 2000.000 +0ns 4000ms
stratum2-1.ntp.led01.ru.> 1 0 0 +0.000 2000.000 +0ns 4000ms
local时间写入RTC。
RTC时间写如后，可以保证/var/log/message和/var/log/dmesg的时间在每次重启后对的。
timedatectl set-local-rtc 1
参考教程 https://www.maketecheasier.com/timedatectl-control-system-time-date-linux/
173.2. 输出时间date¶
[root@root ~]# date "+%Y-%m-%d"
2013-02-19
[root@root ~]# date "+%H:%M:%S"
13:13:59
[root@root ~]# date "+%Y-%m-%d %H:%M:%S"
2013-02-19 13:14:19
[root@root ~]# date "+%Y_%m_%d %H:%M:%S"
2013_02_19 13:14:58
[root@root ~]# date -d today
Tue Feb 19 13:10:38 CST 2013
[root@root ~]# date -d now
Tue Feb 19 13:10:43 CST 2013
[root@root ~]# date -d tomorrow
Wed Feb 20 13:11:06 CST 2013
[root@root ~]# date -d yesterday
Mon Feb 18 13:11:58 CST 2013