A runlevel describes the state that your machine will be running in. Sound redundant?
As an example, if you wanted to remove the yum-updatesd program from runlevel 2, you could simply remove the link /etc/rc.d/rc2.d/S97yum-updatesd.
此文件将提供关于runlevel及在各个runlevel上应当启动的进程的init信息。
Note: if the system appears simply too slow to be bearable, you can exit X-windows by entering runlevel 3.
当更改到一个新的runlevel时，对runlevel文件的更改将被识别。
makefile文件runlevel . mk是控制程序，start5 . mk文件和stop5 . mk文件分别是运行级5时启动和停止服务时的服务依赖描述文件。
To test your installation on Ubuntu V7.10, enter runlevel 1 and start GDM as root, preferably with the -nodaemon option.
Now when Charlie logs in on console (either Ctrl-Alt-F2 to get to a console or enter runlevel 3 as described earlier), he will be asked which role to log in to.
