Synchronize time under Linux

As there are many different linux distributions the procedure might slighty differ for one distribution or another.
The subsequent section explains exemplarily the configuration for Ubuntu Server v12.04 for which GECAMed is officially supported.

1. Open a shell
2. Initially synchronize the system clock once: sudo ntpdate pool.ntp.org
3. Install the network time protocol (NTP) deamon which will communicate with the time servers and synchronize the local clock: sudo apt-get install ntp
4. Open the configuration file of the NTP deamon: sudo nano /etc/ntp.conf
5. Change the time server configuration to contact the luxembourgish ntp-server pool:
   server 0.lu.pool.ntp.org
   server 1.lu.pool.ntp.org
   server 2.lu.pool.ntp.org
   server 3.lu.pool.ntp.org
   (The Luxembourgish pool of NTP servers - lu.pool.ntp.org - will be randomly contacted each hour)
6. Finally restart the NTP service: sudo service ntp restart