Test admin rights within PowerShell script?

Question

Whats the best/easiest way to test for administrative rights in a PowerShell script?

I need to write a script that requires administrative rights and want to know the best way to achieve it.

Answer 1

This is the little function I have in a security module:

function Test-IsAdmin {
    try {
        $identity = [Security.Principal.WindowsIdentity]::GetCurrent()
        $principal = New-Object Security.Principal.WindowsPrincipal -ArgumentList $identity
        return $principal.IsInRole( [Security.Principal.WindowsBuiltInRole]::Administrator )
    } catch {
        throw "Failed to determine if the current user has elevated privileges. The error was: '{0}'." -f $_
    }

    <#
        .SYNOPSIS
            Checks if the current Powershell instance is running with elevated privileges or not.
        .EXAMPLE
            PS C:\> Test-IsAdmin
        .OUTPUTS
            System.Boolean
                True if the current Powershell is elevated, false if not.
    #>
}

Answer 2

In Powershell 4.0 you can use requires at the top of your script:

#Requires -RunAsAdministrator

Outputs:

The script 'MyScript.ps1' cannot be run because it contains a "#requires" statement for running as Administrator. The current Windows PowerShell session is not running as Administrator. Start Windows PowerShell by using the Run as Administrator option, and then try running the script again.