World Library  
Flag as Inappropriate
Email this Article

Shutdown (computing)

Article Id: WHEBN0017699830
Reproduction Date:

Title: Shutdown (computing)  
Author: World Heritage Encyclopedia
Language: English
Subject: Start menu, Wall (Unix), YaST, Windows shell, Cold boot attack
Collection: Operating System Technology, Windows Administration
Publisher: World Heritage Encyclopedia

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 1
    • Windows 1.1
    • Mac OS X 1.2
    • Unix and Linux 1.3
  • See also 2
  • References 3
  • Further reading 4
  • External links 5



In Microsoft Windows, 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 that can shut down the user's computer or another computer on the user's network.

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.[1]

Mac OS X

In Mac OS X 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.[2] 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.[3]

See also


  1. ^
  2. ^  – Darwin and Mac OS X System Manager's Manual
  3. ^  – Linux Administration and Privileged Commands Manual

Further reading

External links

  • – an article about various ways of automated and manual shutting down of Microsoft Windows
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.