将系统引导至单用户状态以执行系统维护，如备份文件系统或对其他系统问题进行故障排除。
# init 0
ok boot -s
SINGLE USER MODE Root password for system maintenance (control-d to bypass): xxxxxx
# reboot -p
由于快速重新引导功能在缺省情况下处于启用状态，因此必须在重新引导系统时指定 –p 选项，从而在引导时显示 GRUB 菜单。要禁用快速重新引导功能以便无需指定 –p 选项，请参见更改缺省快速重新引导行为。
有关在引导时编辑 GRUB 菜单的更多信息，请参见通过在引导时编辑 GRUB 菜单添加内核参数。
# who -r
以下示例显示了在引导过程开始后将基于 SPARC 的系统引导至运行级别 S 时出现的消息。
# init 0
# svc.startd: The system is coming down. Please wait.
svc.startd: 122 system services are now being stopped.
Mar 5 10:30:33 system1 syslogd: going down on signal 15
svc.startd: Killing user processes.
umount: /ws busy
umount: /home busy
Mar 5 17:30:50 The system is down. Shutdown took 70 seconds.
syncing file systems... done
Program terminated
{1c} ok boot -s
SC Alert: Host System has Reset
NOV 17 21:46:59 ERROR: System memory downgraded to 2-channel mode from 4-channel mode
NOV 17 21:47:00 ERROR: Available system memory is less than physically installed memory
NOV 17 21:47:00 ERROR: System DRAM Available: 008192 MB Physical: 016384 MB
Sun Fire T200, No Keyboard
.
.
.
Ethernet address 0:14:4f:1d:e8:da, Host ID: 841de8da.
ERROR: The following devices are disabled:
MB/CMP0/CH2/R0/D0
Boot device: /pci@7c0/pci@0/pci@1/pci@0,2/LSILogic,sas@2/disk@0,0:a
File and args: -s
SunOS Release 5.11 Version 11.2 64-bit
Copyright (c) 1983, 2014, Oracle and/or its affiliates. All rights reserved.
NOTICE: Hypervisor does not support CPU power management
Booting to milestone "milestone/single-user:default".
Hostname: system1
Requesting System Maintenance Mode
SINGLE USER MODE
Enter root password (control-d to bypass): xxxxxx
single-user privilege assigned to root on /dev/console.
Entering System Maintenance Mode
Mar 5 10:36:14 su: 'su root' succeeded for root on /dev/console
Oracle Corporation SunOS 5.11 11.2 July 2014
root@system1:~# who -r
run-level S Mar 5 10:35 S 0 0
root@tsystem1:~#
示例 4-15 x86: 将系统引导至单用户状态（运行级别 S）以下示例显示了在引导过程开始后将基于 x86 的系统引导至运行级别 S 时出现的消息。
root@system-04:~# init 0
root@system-04:~# svc.startd: The system is coming down. Please wait.
svc.startd: 129 system services are now being stopped.
Apr 23 13:51:28 system-04 syslogd: going down on signal 15
svc.startd: Killing user processes.
umount: /home busy
Apr 23 13:51:36 The system is down. Shutdown took 26 seconds.
syncing file systems... done
Press any key to reboot.
.
.
.LSI Corporation MPT SAS BIOS
MPTBIOS-6.26.00.00 (2008.10.14)
Copyright 2000-2008 LSI Corporation.
Initializing..|Press F2 to runS POPUP (CTRL+P on Remote Keyboard)
Press F12 to boot from the network (CTRL+N on Remote Keyboard)
System Memory : 8.0 GB , Inc.
Auto-Detecting Pri Master..ATAPI CDROM 0078
Ultra DMA Mode-2
.
.
.
GNU GRUB version 1.99,5.11.0.175.1.0.0.14.0
****************************************************************************
*Oracle Solaris 11.2 *
* *
* *
* *
* *
* *
* *
* *
* *
* *
* *
****************************************************************************
Use the * and * keys to select which entry is highlighted.
Press enter to boot the selected OS, 'e' to edit the commands
before booting or 'c' for a command-line.
GNU GRUB version 1.99,5.11.0.175.1.0.0.14.0
****************************************************************************
* setparams 'Oracle Solaris 11.2' *
* *
* insmod part_msdos *
* insmod part_sunpc *
* insmod part_gpt *
* insmod zfs *
* search --no-floppy --fs-uuid --set=root cd03199c4187a7d7 *
* zfs-bootfs /ROOT/s11u2/@/ zfs_bootfs *
* set kern=/platform/i86pc/kernel/amd64/unix *
* echo -n "Loading ${root}/ROOT/s11u2 /@$kern: " *
* $multiboot /ROOT/s11u2/@/$kern $kern -B $zfs_bootfs -s
* set gfxpayload="1024x768x32;1024x768x16;800x600x16;640x480x16;640x480x1\ *
* 5;640x480x32" **
****************************************************************************
Minimum Emacs-like screen editing is supported. TAB lists
completions. Press Ctrl-x or F10 to boot, Ctrl-c or F2 for
a command-line or ESC to discard edits and return to the GRUB menu.
Booting a command list
Loading hd0,msdos1,sunpc1/ROOT/s11u2/@/platform/i86pc/kernel/amd64/unix: 0
%...done.
Loading hd0,msdos1,sunpc1/ROOT/s11u2/@/platform/i86pc/amd64/boot_archive:
0%...
.
.
.
SunOS Release 5.11 Version 11.2 64-bit
Copyright (c) 1983, 2014, Oracle and/or its affiliates. All rights reserved.
NOTICE: kmem_io_2G arena created
Booting to milestone "milestone/single-user:default".
Hostname: system-04
Requesting System Maintenance Mode
SINGLE USER MODE
Enter user name for system maintenance (control-d to bypass): root
Enter root password (control-d to bypass): xxxxxxx
single-user privilege assigned to root on /dev/console.
Entering System Maintenance Mode
May 8 11:13:44 su: 'su root' succeeded for root on /dev/console
Oracle Corporation SunOS 5.11 11.2 July 2014
You have new mail.
root@system-04:~# who -r
. run-level S Apr 23 14:49 S 0 0