以 root 身分啟動 x window

x window 是不允許以 root 身分登入的。所以，若想以 root 身分登入，就得先關閉 x window，再以 root 身分啟動 x window。
方法如下：

1. 以一般 user 登入 x window
2. Ctrl-Alt-F2 轉到 tty1
3. 以 root login
4. 鍵入：init 1 (切到個人模式，關閉x window)
5. startx (重啟 x window)

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Standard run levels for Red Hat based distributions Run Level Mode Action

0 Halt Shuts down system

1 Single-User Mode Does not configure network interfaces, start daemons, or allow non-root logins

2 Multi-User Mode Does not configure network interfaces or start daemons.

3 Multi-User Mode with Networking Starts the system normally.

4 Undefined Not used/User-definable

5 X11 As runlevel 3 + display manager(X)

6 Reboot Reboots the system