轉自:https://www.tecmint.com/set-time-timezone-and-synchronize-time-using-timedatectl-command/
1. To display the current time and date on your system, use the timedatectl command from the commandline as follows:
# timedatectl status
Check Time and Date
In the scrrentcast above, RTC time: is the hardware clock time.
2. The time on your Linux system is always managed through the timezone set on the system, to view your current timezone, do it as follows:
# timedatectl OR# timedatectl | grep Time
Check Linux Time Zone
3. To view all available timezones, run the command below:
# timedatectl list-timezones
List All Timezones in Linux
4. To find the local timezone according to your location, run the following command:
# timedatectl list-timezones | egrep -o “Asia/B.*”# timedatectl list-timezones | egrep -o “Europe/L.*”# timedatectl list-timezones | egrep -o “America/N.*”
Find Local Timezone in Linux
5. To set your local timezone in Linux, we will use set-timezone switch as shown below.
# timedatectl set-timezone “Asia/Kolkata”
Set Local Timezone in Linux
It is always recommended to use and set the coordinated universal time, UTC.
# timedatectl set-timezone UTC
Set UTC Time in Linux
You need to type the correct name timezone other wise you may get errors when changing the timezone, in the following example, the timezone “Asia/Kalkata” is not correct therefore causing the error.
Set Correct Timezone in Linux How to Set Time and Date in Linux
6. You can set the date and time on your system, using the timedatectl command as follows: Set Time in Linux
To set time only, we can use set-time switch along the format of time in HH:MM:SS (Hour, Minute and Seconds).
# timedatectl set-time 15:58:30
Set Local Time in Linux Set Date in Linux
7. To set date only, we can use set-time switch along the format of date in YY:MM:DD (Year, Month, Day).
# timedatectl set-time 20151120
Set Date in Linux
8. To set both date and time:
# timedatectl set-time '16:10:40 2015-11-20'
Set Date and Time in Linux How to Find and Set Hardware Clock in Linux
9. To set your hardware clock to coordinated universal time, UTC, use the set-local-rtc boolean-value option as follows:
First Find out if your hardware clock is set to local timezone:
# timedatectl | grep local
Set your hardware clock to local timezone:
# timedatectl set-local-rtc 1
Set Hardware Clock Timezone
Set your hardware clock to coordinated universal time (UTC):
# timedatectl set-local-rtc 0
Set Hardware Clock to UTC Synchronizing Linux System Clock with a Remote NTP Server
NTP stands for Network Time Protocol is a internet protocol, which is used to synchronize system clock between computers. The timedatectl utility enables you to automatically sync your Linux system clock with a remote group of servers using NTP.