How to change Date, Time , Timezone and Hardware Clock (Real Time Clock RTC) in linux from command line (cli)
Date command will display your current date time with time zone.
date Fri Apr 21 13:59:49 IST 2016
To change date and time
date -s "21APR2017 10:06:00"
To change only date
date +%Y%m%d -s "20170421"
To change only time
date +%T -s "11:14:00"
How to change time zone
First take backup of existing localtime file
cp /etc/localtime /backup/localtime_backup
Copy and overwrite existing /etc/localtime file by selecting your prefer timezone file which present in /usr/share/zoneinfo/ directory. eg. I want set timezone to Kolkata.
cp /usr/share/zoneinfo/Asia/Kolkata /etc/localtime
Hardware clock know as Real Time Clock (RTC)
hwclock
If hardware clock is different timezone from system timezone then edit file /etc/sysconfig/clock.
vi /etc/sysconfig/clock
update below timezone
ZONE="Asia/Kolkata" UTC=true ARC=false
you can also set using cli.
hwclock --set --date "21 Oct 2017 21:17" --IST
Then verify both time zone system as well as hardware type
date hwclock
note: It is always advised to reboot the system after changing date time or time zone because some of the services currently running will be holding old time. eg. cronjob, MySQL.
Hello. Great job.
Thanks!