Originally Posted by Alien Bob
The init.d directory (in Slackware, "/etc/init.d" is a symlink to "/etc/rc.d/init.d") has nothing to do with "/etc/inittab".
If you add scripts to init.d they will have to be called with a "start" or "stop" parameter by start- and kill commands which you place in the runlevel directories like "/etc/rc.d/rc3.d" or "/etc/rc.d/rc4.d".
This is all initiated by th SysV rc script "/etc/rc.d/rc.sysvinit".
Which is called by /etc/rc.d/rc.S, /etc/rc.d/rc.K, /etc/rc.d/rc.M, /etc/rc.d/rc.0, and /etc/rc.d/rc.6, all of which are called by the appropriate entries in /etc/inittab.
Plus nothing prevents you from placing a script in /etc/rc.d/init.d and calling it directly from one of the "normal" init scripts.