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In PowerShell V2 you can use background jobs to perform various tasks. You can start a new job by using the Start-Job CmdLet.

PS > Start-Job -Name MyJob -ScriptBlock { Get-Process powershell }

Id              Name            State      HasMoreData     Location             Command
--              ----            -----      -----------     --------             -------
1               MyJob           Running    True            localhost             Get-Process powershell

We can use Get-Job to display the jobs that are available.

PS > Get-Job

Id              Name            State      HasMoreData     Location             Command
--              ----            -----      -----------     --------             -------
1               MyJob           Completed  True            localhost             Get-Process powershell

Notice that the State chenges from Running to Complete after the job completes. To check the result of the Job we use the Receive-Job CmdLet.

PS > Receive-Job -Id 1

Handles  NPM(K)    PM(K)      WS(K) VM(M)   CPU(s)     Id ProcessName
-------  ------    -----      ----- -----   ------     -- -----------
    256      24    53372      60192   566     0,58   1304 powershell
    466      25    61036      71124   570     1,37   5404 powershell

If we run Receive-Job again nothing is returned.

PS > Receive-Job -Id 1

This is because the job results are deleted from the system after you receive them. You can use the Keep parameter to save the results so that you can receive them again.

We can remove a job by using the Remove-Job CmdLet. Here’s a short example.

PS > Get-Job -Id 1 | Remove-Job
PS > Get-Job

If we want to wait for a job to complete we use the Wait-Job CmdLet.

PS > Start-Job -Name MyJob -ScriptBlock { "Hello"; Start-Sleep -s 5 } | Wait-Job

Id              Name            State      HasMoreData     Location             Command
--              ----            -----      -----------     --------             -------
1               MyJob           Completed  True            localhost             "Hello"; Start-Sleep ...

Once the job completes we can use Receive-Job to check the result.

PS > Receive-Job -Name MyJob

Hello

Here’s another example where we add Receive-Job to the pipeline.

PS > Start-Job -Name MyJob -ScriptBlock { "Hello"; Start-Sleep -s 5 } | Wait-Job | Receive-Job

Another cool thing with jobs is that they can be run on Remote Computers. In the Example below we use Invoke-Command and add the AsJob parameter to run the commands as background jobs. Here’s an example.

PS > Invoke-Command -ComputerName DC01,SP01 -ScriptBlock { Get-Process } -AsJob -Credential powershell\administrator

Id              Name            State      HasMoreData     Location             Command
--              ----            -----      -----------     --------             -------
1               Job1            Running    True            dc01,sp01            Get-Process

When running jobs on multiple computers remote each job is stored as a childjob. If we check out the ChildJob parameter on our job we’ll see that there are currently 2 childjobs available, one for each remote computer.

PS > (Get-Job -Id 1).ChildJobs

Id              Name            State      HasMoreData     Location             Command
--              ----            -----      -----------     --------             -------
2               Job2            Completed  True            dc01                  Get-Process
3               Job3            Completed  True            sp01                  Get-Process

If we want to see the result from DC01 we use the Receive-Job CmdLet and point out the Id or Name of that job.

PS > Receive-Job -Name Job2