Start-Job and Group-Object

PowerShell Help
1

I am running a command that groups a list of files by length.

 
$f = Get-Childitem -recurse -file -path c:\documents
$v = $f | Group-Object -property Length | Where {$_.Count -gt 1}

This works fine but I would like to run this command with start-job.

Using the variable $f 


Start-job -scriptblock {param($value)  $value | Group-Object -property Length | Where {$_.Count -gt 1} } -Name GrpLength -Argumentlist $f

$duplicates = Receive-job -name GrpLength



My problem is that this does not return any values.
2

Are you waiting for the job to complete first? There’s really no advantage to using Start-Job if you’re just going to immediately try to fetch the results.

Just for giggles, try adding a unary comma when calling Start-Job:

$scriptBlock = {param($value)  $value | Group-Object -property Length | Where {$_.Count -gt 1} }

Start-job -scriptblock $scriptBlock -Name GrpLength -ArgumentList ,$f

This is because the -ArgumentList parameter accepts an array. If your $f variable contains multiple objects, and you don’t use the comma, then only the first element of the array will be bound to your $value parameter (and the rest would show up in the automatic $args array.) By using the unary comma, $value will be equal to $f (the entire contents of the array).

Or, in this case, you could just not bother with a param block and use the automatic $args variable:

$scriptBlock = {$args | Group-Object -property Length | Where {$_.Count -gt 1} }
Start-job -scriptblock $scriptBlock -Name GrpLength -ArgumentList $f
3

Thank you, I was unaware of the automatic $args variable.

4

Dave,
You had asked if I was waiting for the job to finish. Sorry I did not include that in the original question. I am using Start-job to use a progress bar so the tech using the script will not think that it has stopped on large directory/files. Here is the rest of the section you helped me with.

		$ScriptBlock = {$args | Group-Object -Property Length | where {$_.Count -GT 1}} 
		Start-Job -ScriptBlock $ScriptBlock -Name GrpLength -ArgumentList $ddup
		$i = 0		
		do {Write-Progress -Activity "Grouping files by length Please Wait " -Status "$i Time elapsed in Seconds"
			sleep 1
			$i++
			$job2 = Get-Job -Name GrpLength 
			} 
		while ($job2.state -eq "Running")
		$ddup1 = Receive-Job -Name GrpLength -Keep