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Solaris Run level change

Well finally, I have started to use Solaris. Whenever I get different version of UNIX; I need to find out runlevel related information, as you may need to change runlevel for following causes:

  1. Halt/reboot system when shutdown command don’t work
  2. Troubleshooting or repairing system

The first thing I noticed was /etc/inittab file is different from the Linux version. However, runlevel are quite identical

Default Solaris Run Level

  • S : Single user state (useful for recovery)
  • 0 : Access Sun Firmware ( ok> prompt)
  • 1 : System administrator mode
  • 2 : Multi-user w/o NFS
  • 3 : Multi-user with NFS
  • 4 : Unused
  • 5 : Completely shutdown the host (like performing a power-off @ OBP) [ thanks to Marco ]
  • 6 : Reboot but depend upon initdefault entry in /etc/inittab

Solaris Find out runlevel
To find out current runlevel use who command:

$ who -r


  .       run-level 3  Mar  3 14:04     3      0  S

Solaris changing runlevels after bootup
You need to use init command, for example change runlevel to 2.

# /sbin/init 2

Solaris changing the default runlevel
An entry with initdefault (in /etc/inittab file) is scanned only when init is initially invoked. init uses this entry to determine which run level to enter initially.

Open /etc/inittab file:

# vi /etc/inittab

Find out this entry:


Change is:3 to number you want, don’t use S, 0, 6 ;). Save file.

See also

  • Read man page of inittab and init for more information.
  • There is also a nice program called runlevel for Solaris.

(Check out all of our posts on Solaris)

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{ 8 comments… add one }
  • Anonymous March 3, 2006, 4:57 pm

    The run level 5 completely shutdown the host (like performing a power-off @ OBP)
    I like your blog!

  • LinuxTitli March 3, 2006, 6:01 pm

    I was just wondering about run level 5, under Linux it is for X window.

    Thanks Marco!

  • Anonymous October 11, 2006, 6:38 pm


    I’d like to know about the previos run-level when doing “who -r”

    Why previous run=level is S
    Why not 2? since we’re currently on 3.

  • Nate Duehr May 1, 2007, 10:46 pm

    Some SysV implementations jump straight from S to their final runlevel… others work their way up from the lower ones. Never assume anything in a lower runlevel is EVER started in any other… always create all the symlinks for everything you want running at each level.

  • priyaraj June 13, 2007, 4:02 am

    can i have my oown run levels?

  • Sriram December 14, 2007, 1:57 pm

    Are runlevel S and 1 not same ???

  • Jai Arun August 9, 2011, 12:32 pm

    Yes, Run levels S and 1 are not same… because 1 is a numeric number and S is alphabet.

  • Modiby September 23, 2011, 2:17 am

    Way to answer a 3 and a half year old question

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