Linux Set Date and Time From a Command Prompt

Linux Display Current Data and Time

Just type the date command:
$ date

Sample outputs:

Wed Apr 23 10:32:59 CDT 2014
Linux Display The Hardware Clock (RTC)

Type the following hwclock command to read the Hardware Clock and display the time on screen:
# hwclock -r

OR
# hwclock --show

OR show it in Coordinated Universal time (UTC):
# hwclock --show --utc

Sample outputs:

Wed 23 Apr 2014 10:36:23 AM CDT -0.157239 seconds
Linux Set Date Command Example

Use the following syntax to set new data and time:


date --set="STRING"

For example, set new data to 2 Oct 2006 18:00:00, type the following command as root user:
# date -s "2 OCT 2006 18:00:00"

OR
# date --set="2 OCT 2006 18:00:00"

You can also simplify format using following syntax:
# date +%Y%m%d -s "20081128"

Linux Set Time Examples

To set time use the following syntax:
# date +%T -s "10:13:13"

Where,

10: Hour (hh)
13: Minute (mm)
13: Second (ss)
Use %p locale's equivalent of either AM or PM, enter:
# date +%T%p -s "6:10:30AM"
# date +%T%p -s "12:10:30PM"

How do I set the Hardware Clock to the current System Time?

Use the following syntax:
# hwclock --systohc

OR
# hwclock -w

SEE ALSO:
You can also set new timzone using this mini-howto.
Man pages - hwclock(8), date(1)

http://www.cyberciti.biz/faq/howto-set-date-time-from-linux-command-prompt/