The scripts in this directory are executed each time the system enters this runlevel. The scripts are all symbolic links whose targets are located in /etc/init.d/ . To disable a service in this runlevel, rename its script in this directory so that the new name begins with a 'K' and a two-digit number, and run 'update-rc.d script defaults' to reorder the scripts according to dependencies. A warning about the current runlevels being enabled not matching the LSB header in the init.d script will be printed. To re-enable the service, rename the script back to its original name beginning with 'S' and run update-rc.d again. For a more information see /etc/init.d/README.