Ezine 191 – PowerShell’s Restart-Computer

PowerShell Restart-Computer

Stop Press: I forgot to mention that you need PowerShell v 2.0 for Restart-Computer.

PowerShell v 2.0’s Restart-Computer is very similar to the operating system’s built-in shutdown /r command.  A likely scenario is that you wish to automate the reboot of a local or remote server.  With a tiny substitution to the cmdlet’s verb you could change the command so that it simply shutdown the computer.

Topics for PowerShell Restart-Computer


This Week’s Secret

I have conflicting emotions about PowerShell’s Stop-Computer cmdlet.  On the one hand I want to use this simple command to encourage people to abandon old commands in favour of PowerShell; on the other hand I am disappointed that stop-Computer, and its sister cmdlet restart-Computer, are not as versatile as shutdown.exe.  Just because I rarely use most of the extra switches in old shutdown does not alleviate my irritation that newer PowerShell commands are not both backward compatible and better.

Restart-Computer and Stop-Computer

Restart-Computer is handy for situations where you wish to reboot not just one server, but a whole bunch.  However, let us begin by investigating which PowerShell cmdlets contain the noun ‘computer’.

get-Command -noun computer
# Results include, restart, stop and add.

Researching Restart-Computer

Before we create a working example, as with any new PowerShell cmdlet, it’s worth calling for help so that we can check the syntax and examine the parameters for restart-Computer

get-Help restart-Computer -full

Note 1:  Because I like to inspect the examples, I rarely use get-Help without appending the -full switch.  Two interesting parameters are -force and -credential.  It’s also worth highlighting that restart-Computer uses WMI, hence there are possible firewall restrictions on this command.

Note 2:  In the case of restart-Computer, I can see many opportunities to add the -confirm switch.  Admittedly I reached this conclusion only after I had shot myself in the foot, and downed my local machine instead of the network server I was aiming at.

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Simple Example of Restart-Computer

For once it’s not easy to test this command on the local computer, unless you add the -confirm switch.  As I will explain later, if you specify a network computer with restart-Computer you are probably going to have to disable the firewalls.

restart-Computer -computerName LittleServer

Example of Restart-Computer on Multiple Servers

$Victims ="BigServer, LittleServer, GnomeServer"
restart-Computer -computer $Victims -force

Note 1: This example reboots multiple computers, the names of which are stored in a variable called $Victims.  You could extend this idea and employ get-Content to read the names of the servers stored in a text file.  Incidentally, I have shortened the parameter -computerName to -computer, in PowerShell you can shorten parameters so long as the truncated word is unique and unambiguous.

Problems with Restart-Computer

  • Error Message: The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
  • Cause:  Firewall blocking the WMI / RPC command.
  • Solution:  Turn off the firewall(s), alternatively, try to open just the RPC ports 135 and 445.

Summary of Windows PowerShell Restart-Computer

Restart-Computer is very similar to the old shutdown command which is built-in to generations of Windows operating systems.  The advantage of restart-Computer is that it’s simpler than shutdown, yet offers the ability to reboot a list of servers.  My reason for featuring it is to give people more reasons for abandoning DOS and at least experimenting with PowerShell cmdlets.

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See more PowerShell examples for Shutdown commands

PowerShell Home   • Syntax   • Stop-Computer   • Restart Computer   • Free CSV Import Tool

Get-Credential   • Windows PowerShell   • Windows 8 PowerShell 3.0

Please email me if you have a better example script. Also please report any factual mistakes, grammatical errors or broken links, I will be happy to correct the fault.