Set Time and date.

hwclock - query and set the hardware clock (RTC)

hwclock  is  a  tool for accessing the Hardware Clock.  You can display
       the current time, set the Hardware Clock to a specified time,  set  the
       Hardware  Clock  to  the  System Time, and set the System Time from the
       Hardware Clock.

       You can also run hwclock periodically to insert or remove time from the
       Hardware Clock to compensate for systematic drift (where the clock con-
       sistently gains or loses time at a certain rate if left to run).

hwclock -r or hwclock --show
       hwclock -w or hwclock --systohc
       hwclock -s or hwclock --hctosys
       hwclock -a or hwclock --adjust
       hwclock -v or hwclock --version
       hwclock --set --date=newdate
       hwclock --getepoch
       hwclock --setepoch --epoch=year

       other options:

       [-u|--utc]  --localtime  --noadjfile --directisa --test [-D|--debug]

       and arcane options for DEC Alpha:

       [-A|--arc] [-J|--jensen] [-S|--srm] [-F|--funky-toy]

       Minimum unique abbreviations of all options are acceptable.

       Also, -h asks for a help message.

Follow the steps

 1.check date with date command 

2.set date with date -s command 

3.hwclock --systohc 

4.hwclock --show

Use the following syntax to set new data and time:
date --set="STRING"
date -s "3 MAR 2011 18:00:00"
date --set="3 MAR 2011 18:00:00"
date +%Y%m%d -s "20110303"


To set time use the following syntax:
date +%T -s "12:03:03"