Powershell pass variable to start-job

Question

within powershell I'd like to learn the best way to call a variable to a start job so I don't have to edit the script for each server as it will be specific based on the client I've placed my script on.

$Servername = 'Server1'
    $pingblock = {
      pathping $servername | Out-File C:\client\PS\ServerPing.TXT
    }
    start-job $pingblock

when I run my code above I just get a file with the help as if I forgot the specify the $servername.

Answer 1

Use the -ArgumentList parameter on Start-Job e.g.:

Start-Job -Scriptblock {param($p) "`$p is $p"} -Arg 'Server1'

In your case:

$pingblock = {param($servername) pathping $servername | Out-File C:\...\ServerPing.txt}
Start-Job $pingblock -Arg Server1

Answer 2

To complement Keith Hill's helpful answer with a PSv3+ alternative:

The $using: scope modifier can be used to reference variables in the caller's scope inside the script block passed to Start-Job, as an alternative to passing arguments (by default, a script block executed as a background job does not see any of the caller's variables or other definitions):

PS> $Servername = 'Server1'; Start-Job { "Targeting server " + $using:ServerName } |
                               Receive-Job -Wait -AutoRemoveJob
Targeting server Server1

Note that the same technique can be used when passing a script block for execution on a remote computer to Invoke-Command - see this question.