Now that the changes to the startup configuration are complete, you should restart your system to see if the committed changes are correct. The step is simple yet important. The point of this step is to verify that the changes you made will be persistent. Before your server returns to the network, it is good to verify that a power cycle will not put your server in a state you did not anticipate. As was shown in Table 2-1, runlevel 6 reboots the computer. As the root user , type the following at the command line to restart your computer:
sync;sync; init 6
The sync command here tells your hard drive to flush its buffers to disk. The reason that you do it twice is a longstanding tradition. Once your computer comes back up, log in to the machine as root again and proceed to the next step to verify what you did in step 4.
Another method for restarting your computer is the reboot command. All you need to do is type reboot at a command prompt. As stated in the reboot man page, this is not recommended in older sysvinit releases.