Mastering Windows PowerShell Scripting - Third Edition

Process

The content of the process block runs once for each value received from the pipeline. The built-in $_ variable may be used to access objects in the pipeline within the process block:

function Show-Pipeline {    begin {        $position = $myinvocation.PipelinePosition        Write-Host "Pipeline position ${position}: Start"    }    process {        Write-Host "Pipeline position ${position}: $_"        $_    }}

When an object is passed to the pipeline, the start message will be shown before the numeric value:

PS> $result = 1..2 | Show-PipelinePipeline position 1: StartPipeline position 1: 1Pipeline position 1: 2

Adding Show-Pipeline to the end of the pipeline will show that begin executes twice before process runs:

PS> $result = 1..2 | Show-Pipeline | Show-PipelinePipeline ...