PS script to record powershell version information

Jay Thomas
Jay Thomas used Ask the Experts™
on
Hi all, I have the start of a script which I want to run, parse a text file full of server names and record the PS version to a text file. Here is the script so far:

$computers=get-content c:\work\temp\serverlist.txt

foreach($computer in $computers)

{

invoke-command -computername $computer -scriptblock{$version=(Get-Command powershell).FileVersionInfo.FileVersion }

$result=new-object psobject

$result|Add-Member -MemberType NoteProperty -Name ComputerName -Value $computer

$result |Add-Member -MemberType NoteProperty -Name Version -Value $version

$result|out-file c:\work\temp\result.txt -append

}



But I get the error of:
Invoke-Command : Cannot validate argument on parameter 'ComputerName'. The argument is null or empty. Provide an argument that is
not null or empty, and then try the command again.

Can anyone teak this so it works for me please?
Thank you
Jason
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AlanConsultant

Commented:
Hi Jason,

If it were me having this problem, the first thing I would do it insert a 'Write-Host' command just after you start the ForEach loop thus:

Write-Host $Computer

That will output what the script has pulled from the txt file and is trying to pass to the Invoke-Command.

If you do that, what do you get on screen?


I might also Write-Host what I got into $Computers prior to the start of the loop - again, just to see what it appears to be.


Alan.
Lasse BodilsenSystem Administrator

Commented:
I testet your script and it works fine.  except it don't print the version number in my test?

So as Alan suggested, check your input from c:\work\temp\serverlist.txt and what gets stored in $Computer
Most Valuable Expert 2018
Distinguished Expert 2018
Commented:
Seems like your list is either empty (maybe still open in an editor, but not saved?), or it contains empty lines.
But even with that corrected, your script won't work, because the $version variable will only be set on the remote computer, you can't use it back in the local script.
Try it like this:
Get-Content -Path C:\work\temp\serverlist.txt | Where-Object {$_} | ForEach-Object {
	$ComputerName = $_
	Write-Host "Processing '$($ComputerName)' ..."
	Try {
		Invoke-Command -ErrorAction Stop -ScriptBlock {
			$PSVersionTable | Select-Object -Property @{n='ComputerName'; e={$ENV:ComputerName}}, @{n='PSVersion'; e={$PSVersionTable['PSVersion']}}, @{n='BuildVersion'; e={$PSVersionTable['BuildVersion']}}
		}
	} Catch {
		$_.Exception.Message | Select-Object -Property @{n='ComputerName'; e={$ComputerName}}, @{n='Error'; e={$_}}
	}
} |
	Select-Object -Property ComputerName, PSVersion, BuildVersion, Error |
	Export-Csv -NoTypeInformation -Path C:\work\temp\result.txt

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Lasse BodilsenSystem Administrator
Commented:
or just set the $version before the invoke command, and then test $computer with IF, to check for empty lines.

$computers=get-content c:\work\temp\serverlist.txt

foreach($computer in $computers)
{
if($computer)
    {
    $version = invoke-command -computername $computer -scriptblock{(Get-Command powershell).FileVersionInfo.FileVersion }
    $result = new-object psobject
    $result | Add-Member -MemberType NoteProperty -Name ComputerName -Value $computer
    $result | Add-Member -MemberType NoteProperty -Name Version -Value $version
    $result | out-file c:\work\temp\result.txt -append
    }
}

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Author

Commented:
Hi all, very sorry for the late response.
@ Alan. could you add your command to my script so that I can see what and where I should place it please?

@oBdA - Your script works, there was an empty line in my text file ;)

@ Lasse, what does your script do exactly please?

Thanks all.
Jason
AlanConsultant
Commented:
Hi,

Try this to see what the list is returning:

$Computers=Get-Content C:\Work\Temp\ServerList.txt

ForEach($Computer in $Computers)

{

	Write-Host "The following computer was pulled from the $Computers array and will be used now:  '$($Computer)'"


	Invoke-Command -Computername $Computer -ScriptBlock{$Version=(Get-Command Powershell).FileVersionInfo.FileVersion}

	$Result=New-Object PSObject
	
	$Result | Add-Member -MemberType NoteProperty -Name ComputerName -Value $Computer

	$Result | Add-Member -MemberType NoteProperty -Name Version -Value $Version

	$Result | Out-File C:\Work\Temp\Result.txt -Append

}

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Post back with the results of that, then we can move on to any other issues, but you may want to just use ODBA's script above if it works already.

Thanks,

Alan.
Lasse BodilsenSystem Administrator

Commented:
my script does close to the same as oBdA's, but his script does have Error handling.

if($computer)
{
"Commands"
}

Will check for the string to be empty, and if it is, will not run the commands in the { } brackets, but instead skip to the next string.

Also it moves the $version variable to the start of the invoke-command, so that you set the variable on the local host, instead of the remote host. (as oBdA also mentiones.)
$version = invoke-command -computername $computer -scriptblock{(Get-Command powershell).

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AlanConsultant

Commented:
Hi

What did you get from the script I posted above?

Alan.

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