SysV init

SysV init is a standard process used by Red Hat Linux to control which software the init command launches or shuts off on a given runlevel. SysV init was chosen because it is easier to use and more flexible than the traditional BSD-style init process. The configuration files for SysV init are in the /etc/rc.d/ directory. Within this directory are the rc, rc.local, and rc.sysinit scripts as well as the following directories:

• init.d

• rc0.d

• rc1.d

• rc2.d

• rc3.d

• rc4.d

• rc5.d

• rc6.d

The init.d directory contains the scripts used by the init command when controlling services. Each of the numbered directories represents one of the six default runlevels configured by default under Red Hat Linux. For more information on runlevels, see the section “Init Runlevels” in this chapter.

The default runlevel is listed in /etc/inittab. To find out the default runlevel for your system, look for the line similar to the one below near the top of /etc/inittab:

id:3:initdefault:

The default runlevel listed in the example above is 3, as the number after the first colon indicates. If you want to change it, edit /etc/inittab as root.

Warning

Be very careful when editing /etc/inittab. Simple typos can cause your system to become unbootable. If this happens, you will either need a boot diskette for your system or you will need to enter rescue mode to boot your computer and fix the file.

Cross-Reference

For more information on rescue mode, see Appendix B.