Powershell command works in Powershell but not inside of a script, why?

powershell iis powershell-4.0 web-administration

Add this line at the top of your script, it will import the necessary IIS module:

Import-Module WebAdministration;

EDIT, thanks to @KyleMit: if you don't have WebAdministration installed, you may need to first run (with elevated privilege)

Import-Module ServerManager; Add-WindowsFeature Web-Scripting-Tools

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