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Boot into Single User Mode

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Mike Gerdts has a nice blog entry on how to Boot OpenSolaris into Single User Mode.  Unfortunately, it appears that his image links are broken, so the screen snapshots that he refers to in the text are not visible (at least, not when using Firefox 2 on OpenSolaris 2008.05).

So I have taken his instructions, made a few edits, and provided screen snapshots of my own.

When you first start the machine, you will see a GRUB menu.  The exact contents will vary, but there should be at least one entry for OpenSolaris.  As an example, this is from one of my machines:

With the entry for OpenSolaris highlighted, press the 'e' key and that should take you to:

In the example shown above, I used the down-arrow key on the keyboard to highlight the second line, since that is the one I want to edit.  I press the 'e' key again to edit that line, which takes me to:

Add -s to the end of that line: 

And then press the Enter key to go back to the list of commands:

Press the 'b' key and the system will begin to boot. You will eventually be prompted for the root password:

After you put in the root password, a shell prompt will be displayed and you're ready to do whatever system administration is needed that requires single user mode. 

When you no longer need single user mode, you can have the boot process pick up where it left off.  As the documentation points out, all you have to do is press Ctrl-D.  

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Comments ( 6 )
  • Mike Gerdts Sunday, September 14, 2008

    Thanks for finishing this off for me...

    I was mainly doing this as notes to myself and a test of ScribFire's interactions with Blogger and WordPress. I thought that I had left it in a draft (not publicly viewable) stage when I gave up on thinking that ScribeFire was going to be a big improvement over the mediocre to bad native blog editing interfaces.

    I've added a link to your page for those that stumble upon mine.

  • Mr. Black Saturday, February 14, 2009

    Thanks! You Da Man.

    I have read several other web pages but you explained it the best.

    My problem was I forgot my main user's password but remembered root. (uuh.derrrr.)

    Root was not allowed to use roles!

    I might fix that next but I kinda like the extra security.

  • Paul Wednesday, May 13, 2009

    I have a similar problem in that I deleted the password on my main account and then the screen saver engaged. Now, I can't logon to either my main or root. I tried your suggestion but the boot seems to be hung on the splash page with the scanning orange slice.

  • Paul Wednesday, May 13, 2009

    The 8.11 release installs with three entries on the Grub screen. The regular boot, a Diagnostic boot, and a 'text screen' boot. If you edit the 'text screen' boot as described then it works as expected. For some reason the GUI boot just seem to hang. Thanks for the pointer!

  • Dan Beam Tuesday, January 12, 2010


    Similar thing happened to me as well using 2009.06 (after adding -s to the kernel boot string). I was about to give up when I pressed CTRL and I was prompted with the screen at the bottom of the tutorial.

    Hope this helps some other silly fellow like me that accidentally turns on PAM and doesn't run passwd before logging off or putting up the screen saver, :(

  • mithun Saturday, November 13, 2010


    i have login in opensolaris console with userid and password ,now i m doing my work but suddenly screen get clear and black screen shows with some GUI cursor ,then system doesnt allow to do any thing not even prompt also comes , what do i do? can u help me out!

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