Shutdown (computing)

To shut down or power off a computer is to remove power from a computer's main components in a controlled way. After a computer is shut down, main components such as CPUs, RAM modules and hard disk drives are powered down, although some internal components, such as an internal clock, may retain power.

Implementations

Windows and ReactOS

In Microsoft Windows and ReactOS, a PC or server is shut down by selecting the Shutdown item from the Start menu on the desktop. Options include shutting down the system and powering off, automatically restarting the system after shutting down, or putting the system into stand-by mode.

There is also a shutdown command that can be executed within a command shell window. shutdown.exe is the command-line shutdown application(located in %windir%\System32\shutdown.exe)^[1] that can shut down the user's computer or another computer on the user's network. Different parameters allow different functions. More than one parameter can be used at a time for this command.^[2]

Parameter	Function
-l	Logs off a user. This is the default even without using any parameters.
-a	Stops shutdown.exe. It is used during a time-out period.
-f	Kills all running applications.
-s	Turns off the computer.
-r	Shuts down and reboots a computer.
-m[\\ Computer Name]	When shutting down a network computer, allows you to choose which computer to turn off.
-t xx	Timer before shut down occurs. By default it is set to 20 seconds.
-c "message"	Allows a message to be shown in the System Shutdown window. It can not be more than 127 characters.

Just like other operating systems, Windows has the option to prohibit selected users from shutting down a computer. On a home PC, every user may have the shutdown option, but in computers on large networks (such as Active Directory), an administrator can revoke the access rights of selected users to shut down a Windows computer. Nowadays there are many software utilities which can automate the task of shutting down a Windows computer, enabling automatic computer control. The Windows Shutdown website lists various software utilities to automate the task of shutting down.

In Windows, a program can shut down the system by calling the ExitWindowsEx or NtShutdownSystem function.^[3]

macOS

In macOS the computer can be shut down by choosing "Shut Down…" from the Apple Menu or by pressing the power key to bring up the power management dialog box and selecting button "Shut down". An administrator may also use the Unix shutdown command as well.^[4] It can also be shut down by pressing [Alt]+[Command]+[Eject optical disc on optical drive] but this will not prompt the user anything at all.

Unix and Linux

In Unix and Linux, the shutdown command can be used to turn off or reboot a computer. Only the superuser can shut the system down.

One commonly issued form of this command is shutdown -h now, which will shut down a system immediately. Another one is shutdown -r now to reboot. Another form allows the user to specify an exact time or a delay before shutdown: shutdown -h 20:00 will turn the computer off at 8:00 PM, and shutdown -r -t 60 will automatically reboot the machine within 60 seconds (one minute) of issuing the command.^[5]

References

^ "Shut down Windows 10 with just one click (or two)". CNET. Retrieved 24 April 2017.
^ "Shutdown". technet.microsoft.com. Retrieved 24 April 2017.
^ "NtShutdownSystem". 25 February 2001. Archived from the original on 2 September 2014. Retrieved 11 April 2015. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
^ shutdown(8) – Darwin and macOS System Manager's Manual
^ shutdown(8) – Linux Administration and Privileged Commands Manual

External links

shutdown.cc – an article about various ways of automated and manual shutting down of Microsoft Windows

[1] "Shut down Windows 10 with just one click (or two)". CNET. Retrieved 24 April 2017.

[2] "Shutdown". technet.microsoft.com. Retrieved 24 April 2017.

[3] "NtShutdownSystem". 25 February 2001. Archived from the original on 2 September 2014. Retrieved 11 April 2015. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)

[4] shutdown(8) – Darwin and macOS System Manager's Manual

[5] shutdown(8) – Linux Administration and Privileged Commands Manual

[1]

[2]

[3]

[4]

[5]

v t e Unix command-line interface programs and shell builtins
File system	cat chattr chmod chown chgrp cksum cmp cp dd du df file fuser ln ls mkdir mv pax pwd rm rmdir split tee touch type umask
Processes	at bg crontab fg kill nice ps time
User environment	env exit logname mesg talk tput uname who write
Text processing	awk basename comm csplit cut diff dirname ed ex fold head iconv join m4 more nl paste patch printf read sed sort strings tail tr troff uniq vi wc xargs
Shell builtins	alias cd echo test unset wait
Searching	find grep
Documentation	man
Software development	ar ctags lex make nm strip yacc
Miscellaneous	bc cal expr lp od sleep true and false
Categories Standard Unix programs Unix SUS2008 utilities List

v t e Windows command-line programs and shell builtins
COMMAND.COM Command Prompt Windows PowerShell Recovery Console
File system navigation	cd (chdir) dir popd pushd tree
File management	attrib cacls cipher compact copy del (erase) deltree icacls mkdir (md) mklink move openfiles recover ren (rename) replace rmdir (rd) robocopy takeown xcopy
Archiving	expand extrac32 extract makecab pax tar
Disk management	chkdsk convert defrag diskcomp diskcopy diskpart diskraid diskshadow drvspace fdisk format fsutil label manage-bde refsutil subst scandisk sys vol vssadmin
Processes	at exit kill powercfg runas sc schtasks shutdown start taskkill tasklist
Registry	assoc ftype reg regini regsvr32
User environment	chcp cmdkey date graftabl mode path set setver setx time title ver where whoami
File contents	comp edit edlin fc find findstr print type
Scripting	choice clip cscript doskey echo for forfiles goto if more pause prompt rem timeout
Networking	arp bitsadmin curl getmac hostname ipconfig nbtstat net netsh netstat nslookup PathPing ping rpcping route scp setspn sftp ssh ssh-add ssh-agent ssh-keygen ssh-keyscan tracert winrm winrs
Maintenance and care	auditpol dispdiag driverquery eventcreate eventtriggers logman mofcomp msiexec ntbackup pnpunattend pnputil REAgentC relog sfc sxstrace systeminfo tracerpt typeperf w32tm WBAdmin wecutil wevtutil winmgmt winsat wmic
Boot management	bcdedit bootcfg bootsect fixboot fixmbr
Software development	debug exe2bin QBasic
Miscellaneous	break cls dism dpath gpresult gpupdate help MSCDEX pentnt tpmtool tpmvscmgr wsl
List of DOS commands Environment variables Windows Support Tools