How can I run a pipeline with variables in a background task in Powershell?

Question

I'm trying to run two large sort processes simultaneously. So far, I've been unable to run one of these processes in the background.

Here's what I'm doing:

Get-Content $attfile |Sort-Object { 
  [datetime]::ParseExact($_.Substring(0, 23), 'dd/MM/yyyy HH:mm:ss.fff', $null) 
} | out-file -filepath "$new" -Encoding ascii 


Get-Content $navfile | Sort-Object { 
  [datetime]::ParseExact($_.Substring(0, 23), 'dd/MM/yyyy HH:mm:ss.fff', $null) 
} 2> $null | out-file -filepath "$navnew" -Encoding ascii

I would like to run the first sort in the background so that I don't have to wait for the first sort to finish. How can I do this? I find the powershell documentation of Start-Job very confusing.

Answer 1

You can pass arguments to the job's scriptblock via the -ArgumentList parameter:

$job = Start-Job -ScriptBlock {
  param($inPath,$outPath)

  Get-Content $inPath |Sort-Object { 
    [datetime]::ParseExact($_.Substring(0, 23), 'dd/MM/yyyy HH:mm:ss.fff', $null) }
  } |Out-File $outPath
} -ArgumentList $attfile,$new

# do the other sort in foreground here ...

$job |Wait-Job

if($job.State -eq 'Completed'){
  # background sort succeeded, you can read back $new now
}