How do I update my system clock? I aways forget the command I have to lauch for having my system clock updated. I don't want to configure the ntp daemon or activate automatic time updates. I just want to launch a command and sync my system time with a Time Server . So, lets do it!
You first have to select a ntp server near to you. Go to pool.ntp.org webpage and choose the country you are living in. Then, choose a server and execute this command:
sudo ntpdate 0.europe.pool.ntp.org 29 Mar 17:33:25 ntpdate: step time server 126.96.36.199 offset 2.770018 sec
I had a difference of two seconds between the Real Hour and my system hour. If I execute the command again you will see that now the difference is negligible:
sudo ntpdate 0.europe.pool.ntp.org 29 Mar 17:33:40 ntpdate: adjust time server 188.8.131.52 offset 0.000176 sec
Hope it has been helpful! Take care.
 In this post you'll find all the instructionson how to create a ntp server, though.