Runlevel

Runlevel :

Runlevel defins what services or processes should be running on the system. The init process can run the system in one of seven runlevels. The system runs only one of the seven runlevel at a time.

Main run levels are:

0 : Halt system ( shutdown ) . Do not set this
1 : single user mode
2 : Basic multi user mode without NFS.
3 : Full multi user mode ( text base )
4 : un-used.
5 : Multi user mode with graphics.
6 : Reboot system. Do not set this.
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1> Configuration file
/etc/inittab
id : 5 : init default

2> Check current and previous runlevel.
#runlevel

N : No number ( if no change in runlevel then it shows previous level = N )

3> Change runlevel temporarily.

#init number

eg. # init 0 ——shutdown.
Or
#telinit ———> same function as init command.

4> Change runlevel permantantly.
We need to make changes in configuration file.

#vi /etc/inittab
id : 3 : init default

:wq

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