Linux/etc/inittab six operating levels for a simple understanding

Configuration file, the system will read the information of this file during the startup process.

[Email protected] ~]# Cat/etc/inittab

# Inittab is a used by upstart for the default runlevel.

#

# ADDING Other CONFIGURATION here would have NO EFFECT on YOUR SYSTEM.

#

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

#

# individual runlevels is started by/etc/init/rc.conf

#

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

#

# Terminal Gettys is handled by/etc/init/tty.conf and/etc/init/serial.conf,

# with configuration In/etc/sysconfig/init.

#

# For information on what to write upstart event handlers, or how

# Upstart works, see Init (5), init (8), and Initctl (8).

# These are the explanations for the file, and the following 0-6 is the explanation of the RunLevel

# Default RunLevel. The runlevels used is:

# 0-halt (do not set Initdefault to this)

turn off the machine

# 1-single User mode

Single-user mode ( one person plays a single machine.) only one user can log in and no default password is required, no NIC. ）

# 2-multiuser, without NFS (the same as 3, if you don't have networking)

If you don't run the network, it's the same as level three.

# 3-full multiuser modes Multi-user mode (command mode that we often use)

# 4-unused is not used, system retention level

# 5-x11 Desktop mode

# 6-reboot (do not set Initdefault to this) reboot

#

ID: 3: initdefault: here is where this file is configured, in command mode, the default is level--3--。

Here can not be changed, if you change to 0,1,6 your system will not turn on the machine

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Linux/etc/inittab six operating levels for a simple understanding