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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
• Restart-Computer and Stop-Computer
• Simple Example of 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'.

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

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.

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.

Example of Restart-Computer on Multiple Servers

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.

If you are looking for handy network utilities, try some of the free downloads at Tools4Ever

See more Microsoft PowerShell tutorials

• Windows PowerShell Home  • Introduction  • Cmdlets  • Exchange 2007  • Profile.ps1  • $_.Pipeline

If you see an error of any kind, do let me know.  Please report any factual mistakes, grammatical errors or broken links, I will be happy to not only to correct the fault, but also to give you credit.

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