In PowerShell, $_ is a special variable that represents the current object in the pipeline. It can be used in scripts and commands to refer to the object that is being processed at that time. For example, consider the following script: Get-Process | ForEach-Object { Write-Output "$($_.Name) is running on the system." } This script will get a list of all the processes running on the system, and for each process it will output a message that includes the name of the process. The $_ variable is used to refer to the current process object being processed in the pipeline, and the Name property of the object is used to get the name of the process. $_ can be used in many different contexts in PowerShell, including in script blocks, loops, and filters. It is a powerful and versatile tool that can be used to simplify and streamline your scripts and commands.