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PowerShell 2.0: One Cmdlet at a Time #34 Invoke-Commmand
Posted on January 8th, 2010 2 commentsContinuing the series looking at new cmdlets available in PowerShell 2.0. This time we look at the Invoke-Command cmdlet.
What can I do with it?
Run commands on local or remote computers and return the results.
Examples:
Establish a persistent remote PowerShell connection to Test01 using New-PSSession and store it in the variable $session. Then return the results for which services begin with T.
$session = New-PSSession -ComputerName Test01 Invoke-Command -Session $session -ScriptBlock {Get-Service | Where-Object {$_.name -like 'T*'}}
You can see that the results contain a property PSComputerName that shows which server the results came from.
You don’t need to stretch your imagination too far to see how this could quickly become extremely powerful. Imagine instead that you used New-PSSession to make sessions to 100 servers stored in a csv file and run the same command to all of those servers. The change in the code would be very small.
$sessions = New-PSSession -ComputerName (Get-Content servers.csv) Invoke-Command -Session $sessions -ScriptBlock {Get-Service | Where-Object {$_.name -like 'T*'}}
How could I have done this in PowerShell 1.0?
Remoting did not exist in PowerShell 1.0, you would have needed to use Remote Desktop to run an interactive session on a remote server.
2 responses to “PowerShell 2.0: One Cmdlet at a Time #34 Invoke-Commmand”
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Hi Jonathan, great series. I noticed you used the following in a few of your examples:
-ComputerName (Import-Csv servers.csv)
Does this actually work? The parameter accepts an array of strings which Import-Csv does not return.
Regards,
Arnoud -
Jonathan Medd January 14th, 2010 at 22:31
Thanks for the feedback it’s good to know someone is keeping tabs on me!
You are absolutely correct and I have to admit to being slightly lazy with that example and not actually testing it, I think that is the only example I did not test in this series! My excuse was that it was in the help file for New-PSSession, see example 9.
http://technet.microsoft.com/en-us/library/dd347668.aspx
I have updated the series to use (Get-Content servers.csv) instead and also filed a documentation bug which I would be more than happy if you voted for:
https://connect.microsoft.com/PowerShell/feedback/ViewFeedback.aspx?FeedbackID=525002
Thanks again and make sure you keep checking for other mistakes!
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Arnoud Jansveld January 14th, 2010 at 19:03