Most Linux distributions (including Red Hat) use the "System V" method of initialization. The /etc directory has a rc.d directory. That directory contains other directories, one for each init level (2,3,5,etc) in the form of rc?.d (where ? is 2,3, etc). Inside that directory are symlinks with names like Snn<name of program> or Knn<name of program>. The S means "start", and the K means "kill". The numbers represented by nn is the relative position in the startup order. A script called S10foo will execute prior to S20bar, etc.
The reason symlinks are used is because the particular daemon or sevice could be started at multiple run levels. You wouldn't want 3 different copies of the exact same startup script. The actual scripts are in /etc/rc.d/init.d.