this command is used to liast all the available services and view or update their run level status
$chkconfig --list
startup of a particular service
$chkconfig --list | grep network
sorts services alphabatically and displays according to their current startup run level
$ chkconfig --list |sort
shows only the running services
$chkconfig --list |grep on
shows the services running at the particular level
$chkconfig --list| grep: 5 on
it overrides the services
$ chkconfig --oveerride
to find all disabled services
$ chkconfig --list |grep off