As described above, rc.sysinit runs /etc/host_cfg/$HOSTNAME/rc.d/rc.local or /etc/rc.d/rc.local, if the file exists and is executable.

You can use the rc.local file to customize your startup by:

You can also use rc.local to slay running processes and restart them with different options, but this is a heavy-handed approach. Instead of doing this, modify the device enumeration to start the processes with the correct options. For more information, see "Device enumeration," earlier in this chapter.

For example, you can:

Don't use the rc.local file to to set up environment variables, because there's another shell that starts after this script is run, so any environment variable that you set in this file disappears by the time you get a chance to log in.

Note: After you've created rc.local, make sure that you set the executable bit on the file with the command:
chmod +x rc.local