求高手分析下这个inittab文件

yel617

# /etc/inittab: init(8) configuration.
# $Id: inittab,v 1.91 2002/01/25 13:35:21 miquels Exp $

# The default runlevel.
id:3:initdefault:

# Boot-time system configuration/initialization script.
# This is run first except when booting in emergency (-b) mode.
si::sysinit:/etc/init.d/rcS

# What to do in single-user mode.
~~:S:wait:/sbin/sulogin

# /etc/init.d executes the S and K scripts upon change
# of runlevel.
#
# Runlevel 0 is halt.
# Runlevel 1 is single-user.
# Runlevels 2-5 are multi-user.
# Runlevel 6 is reboot.

l0:0:wait:/etc/init.d/rc 0
l1:1:wait:/etc/init.d/rc 1
l2:2:wait:/etc/init.d/rc 2
l3:3:wait:/etc/init.d/rc 3
l4:4:wait:/etc/init.d/rc 4
l5:5:wait:/etc/init.d/rc 5
l6:6:wait:/etc/init.d/rc 6
# Normally not reached, but fallthrough in case of emergency.
z6:6:respawn:/sbin/sulogin

# What to do when CTRL-ALT-DEL is pressed.
ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now

# Action on special keypress (ALT-UpArrow).
#kb::kbrequest:/bin/echo "Keyboard Request--edit /etc/inittab to let this work."

# What to do when the power fails/returns.
pf::powerwait:/etc/init.d/powerfail start
pn::powerfailnow:/etc/init.d/powerfail now
po::powerokwait:/etc/init.d/powerfail stop

# This line provides a nice out-of-box experience. For regular use, you
# should replace it with the proper getty lines below.
con:2345:respawn:/sbin/getty console

# /sbin/getty invocations for the runlevels.
#
#
# The "id" field MUST be the same as the last
# characters of the device (after "tty").
#
# Format:
# <id>:<runlevels>:<action>:<process>
#
# Uncomment these for a devfs system
#
#1:2345:respawn:/sbin/getty 38400 vc/1
#2:23:respawn:/sbin/getty 38400 vc/2
#3:23:respawn:/sbin/getty 38400 vc/3
#4:23:respawn:/sbin/getty 38400 vc/4
#5:23:respawn:/sbin/getty 38400 vc/5
#6:23:respawn:/sbin/getty 38400 vc/6
#
# Uncomment these only for non-devfs systems
#
#1:2345:respawn:/sbin/getty 38400 tty1
#2:23:respawn:/sbin/getty 38400 tty2
#3:23:respawn:/sbin/getty 38400 tty3
#4:23:respawn:/sbin/getty 38400 tty4
#5:23:respawn:/sbin/getty 38400 tty5
#6:23:respawn:/sbin/getty 38400 tty6

# Example how to put a getty on a serial line (for a terminal)
#
# Uncomment these for a devfs system
#
#T0:23:respawn:/sbin/getty -L tts/0 9600 vt100
#T1:23:respawn:/sbin/getty -L tts/1 9600 vt100
#
# Uncomment these only for non-devfs systems
#
#T0:23:respawn:/sbin/getty -L ttyS0 9600 vt100
#T1:23:respawn:/sbin/getty -L ttyS1 9600 vt100

# Example how to put a getty on a modem line.
#
# Uncomment this for a devfs system
#
#T3:23:respawn:/sbin/mgetty -x0 -s 57600 tts/3
#
# Uncomment these only for non-devfs systems
#
#T3:23:respawn:/sbin/mgetty -x0 -s 57600 ttyS3

atiansk

一般地，3 - Full multiuser mode

5 - X11

其它的不懂。

kamingli

一开始, 根据执行的level, 执行rc x, 等rc x执行完后,  con:2345:respawn:/sbin/getty console 就登录了,
如果按下了CTRL-ALT-DEL 就执行
ca:12345:ctrlaltdel:/sbin/shutdown -t1 -a -r now

如果有UPS等设备, 而设备又检测到如掉电等事件, 就根据事件执行如下.
pf::powerwait:/etc/init.d/powerfail start
pn::powerfailnow:/etc/init.d/powerfail now
po::powerokwait:/etc/init.d/powerfail stop