两个关于linux的问题，请高手指点。。

jeffy_wang

1 what two runlevels do linux systems commonly boot to and how do they differ?

2 How does one configure a Linux system so that single user mode is not a security problem?(What file does one have to modify, and how does one have to modify it?)

kns1024wh

出于不同的管理目的，使用的具体的工具