x86: How to Boot a System to Run Level S (Single-User Level)

Use this procedure to boot a system (that is currently at run level 0) to run level S.

1. If the system displays the Type any key to continue prompt, press any key to reboot the system.

   You can also use the reset button at this prompt. If the system is shut down, turn the system on with the power switch.

   The Current Boot Parameters menu is displayed after a few minutes.

2. Type b -s to boot the system to run level S. Press Enter.

   If you do not make a selection within five seconds, the system is automatically booted to run level 3.

3. Type the superuser password, if prompted.

4. Verify that the system is at run level S by using the who -r command.

   # who -r . run-level S Jul 19 14:37 S 0 3

5. Perform the maintenance task that required the run level change to S.

6. Press Control-D to bring the system back to run level 3.

x86: Example—Booting a System to Run Level S (Single-User Level)

Type any key to continue
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                     <<< Current Boot Parameters >>>
Boot path: /pci@0,0/pci-ide@7,1/ide@0/cmdk@0,0:a
Boot args: 
Type    b [file-name] [boot-flags] <ENTER>      to boot with options
or      i <ENTER>                               to enter boot interpreter
or      <ENTER>                                 to boot with defaults
 
 
                     <<< timeout in 5 seconds >>>

Select (b)oot or (i)nterpreter: b -s
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INIT: SINGLE USER MODE

Type Ctrl-d to proceed with normal startup,
(or give root password for system maintenance):  xxx
Entering System Maintenance Mode
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# who -r
   .       run-level S  Jul 19 14:37     S      0  3
(Perform some maintenance task)
# Press Control-D