chkconfig is a Linux tool to view and modify information about runlevel configuration files, viz., maintaining the /etc/rc[0-6].d directory hierarchy by relieving system administrators of the task of directly manipulating the numerous symbolic links in those directories.
The Linux version directly manages the symlinks in /etc/rc[0-6].d. This leaves all of the configuration information regarding what services init starts in a single location. chkconfig has five distinct functions: adding new services for management, removing services from management, listing the current startup information for services, changing the startup information for services, and checking the startup state of a particular service. When chkconfig is run without any options, it displays usage information.
List which services are available and in which runlevel they are started: