Set Clock

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Josh Owings
Frequent Advisor

Set Clock

Can anyone tell me how to set the system time in Red Hat 7.1?
Should I/Can I sync the hardware clock to this new time. If so how would I go about doing so?
Kodjo Agbenu
Honored Contributor

Re: Set Clock


To set system date/time using command-line (as root) :

root@mycomputer# date MMDDhhmm

Where :
MM -> month (01..12)
DD -> day (01..31)
hh -> hour (00..23)
mm -> minute (00..59)

Nobody can't tell you if you should synchronize system time with hardware clock. If you were located on the Greenwitch Meridian Timezone (GMT), I would say : of course yes, you have to do os.

In any other case, I can say : it's up to you.
Some people say that you should set the hardware clock to GMT (also called UTC) and use the TIMEZONE environment variable to specify the time shift between UTC and your local meridian.
For my part, I set hardware clock directly to my local time.

To synchronize hardware clock with system clock (or vice-versa) :

root@mycomputer# hwclock --systohc

To get all options :

root@mycomputer# hwclock --help

Good luck.


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Josh Owings
Frequent Advisor

Re: Set Clock

That is exactly what I was looking for.
Thank you!
Bernie Vande Griend
Respected Contributor

Re: Set Clock

Tried to post this earlier, but it crashed on me.

date is great for setting time manually, but ntpd is the way to go to ensure time is always accurate.
You can also use ntpdate to sync time immediately to an ntp server at your site or on the internet.
Example: /usr/sbin/ntpdate -b -s -p 8
This syncs time among 3 internet NTP servers.
If you put servers like these in /etc/ntp.conf and start ntpd then your time should always be accurate.
Ye who thinks he has a lot to say, probably shouldn't.
Josh Owings
Frequent Advisor

Re: Set Clock

Unfortunately the box in question only has internal connectivity at the moment as I am short an NIC card. But, thank you for the reply.