init 0-6 （啓動級別:init 0,1,2,3,4,5,6）

啓動級別:

init 0,1,2,3,4,5,6 這是個好久的知識點了，只是本身一直都迷迷糊糊的，今天在翻出來好好理解下。。

• 0: 停機
• 1：單用戶形式，只root進行維護
• 2：多用戶，不能使用net file system
• 3：徹底多用戶
• 4：安全模式
• 5：圖形化
• 6：重啓

編輯 /etc/inittab 文件，能夠修改系統默認啓動級別

[root@localhost ~]# cat /etc/inittab
# inittab is only used by upstart for the default runlevel.
#
# ADDING OTHER CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#
# System initialization is started by /etc/init/rcS.conf
#
# Individual runlevels are started by /etc/init/rc.conf
#
# Ctrl-Alt-Delete is handled by /etc/init/control-alt-delete.conf
#
# Terminal gettys are handled by /etc/init/tty.conf and /etc/init/serial.conf,
# with configuration in /etc/sysconfig/init.
#
# For information on how to write upstart event handlers, or how
# upstart works, see init(5), init(8), and initctl(8).
#
# Default runlevel. The runlevels used are:
#   0 - halt (Do NOT set initdefault to this)
#   1 - Single user mode
#   2 - Multiuser, without NFS (The same as 3, if you do not have networking)
#   3 - Full multiuser mode
#   4 - unused
#   5 - X11
#   6 - reboot (Do NOT set initdefault to this)
#
id:5:initdefault:
[root@localhost ~]#

Linux 的系統啓動級別