FreeBSD > Init to reboot or shutdown system

Posted on in Categories News last updated February 23, 2005

FreeBSD init works different ways. In BSD style, it specifies the kernel security level as follows:
-1: Permanently insecure mode.
0: Insecure mode
1: Secure mode
2: Highly secure mode
3: Network secure mode

You can get current security level (FreeBSD runlevel) using sysctl command:
# sysctl –a | grep kern.securelevel

You can setup new security level in /etc/rc.conf file:
1) Open file in text editor
# vi /etc/rc.conf

2) Add or modify following:
kern_securelevel_enable=”YES” # kernel security level
kern_securelevel=”2″ # range: -1..3 as above

3) Save the changes. Exit and restart FreeBSD.

If init used from command line i.e as a user process, init will emulate AT&T System V UNIX behavior as follows:

0: Halt and turn the power off
1: Go to single-user mode
6: Reboot the machine
c: Block further logins
q: Rescan the /etc/ttys file

1) To halt and turn the power off type:
# init 0

2) You can also use normal halt or shutdown command to shutdown system.

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

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