The rc.sysinit file initializes various system components such as the serial ports. The rc.local file provides a means for you to run your own scripts and applications during the boot process. To do this simply enter Linux single on yourlilo prompt and your Linux box will give you a single user root shell, without requiring the password. You can also use the command telinit to switch between run levels. There are two different types of symlink, a hard link and a soft link.
Hard links appear as normal directories, they simply mirror the files contained in the parent.
Soft links work differently. The command to create links is called ln. To create a soft link simply use ln-s and specify the source and target. See man ln for further help. Until Red Hat create the RPM package system, if you wanted to add or remove an application or service from your Linux server you had to track down all the files associated with it and delete them.