运行级别

# inittab is only used by upstart for the default runlevel.

#inittab仅仅用于确定启动时的开机级别

# ADDING OTHER CONFIGURATION HERE WILL HAVE NO EFFECT ON YOUR SYSTEM.
#

# System initialization is started by /etc/init/rcS.conf

#/etc/init/rcS.conf被用于系统初始化启动（硬件初始化）

#

# Individual runlevels are started by /etc/init/rc.conf

#/etc/init/rc.conf被用于系统初始化操作（各项服务的启动脚本）

#

# Ctrl-Alt-Delete is handled by /etc/init/control-alt-delete.conf

#Ctrl-Alt-Delete被/etc/init/control-alt-delete.conf文件设置

#

# Terminal gettys are handled by /etc/init/tty.conf and /etc/init/serial.conf,

# with configuration in /etc/sysconfig/init.

#终端设置文件为/etc/init/tty.conf and /etc/init/serial.conf,

#终端具体配置文件为/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)

#     关机         

#   1 - Single user mode

#     单用户模式

#   2 - Multiuser, without NFS (The same as 3, if you do not have networking)

#     不支持NFS的多用户模式

#   3 - Full multiuser mode

#     完整的多用户模式

#   4 - unused

#     保留项

#   5 - X11

#     图形界面

#   6 - reboot (Do NOT set initdefault to this)

#     重启

id:3:initdefault:                   #设定系统默认的启动级别