Often when working with PowerShell you want to start an external process and wait for its completion. An example of this might look like this:

Write-Host "Show before starting Notepad"

Notepad.exe

Write-Host "Show after closing Notepad"

But this script prints the second line directly after starting notepad. There are several solutions possible, but this one has proved very useful.

Write-Host "Show before starting Notepad"

Notepad.exe | Out-Null

Write-Host "Show after closing Notepad"

Simply add Out-Null after the invocation of notepad and PowerShell will wait until it continues executing the script.