Add a new Farm Administrator in SharePoint 2013

AddFarmAdmin.ps1

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# Add a new Farm Administrator
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# Creates a new Farm Administrator
$newFarmAdministrator = “MC\Sp.AdminMC"

$caWebApp = Get-SPWebApplication -IncludeCentralAdministration | where-object {$_.DisplayName -eq "SharePoint Central Administration v4"}
$caSite = $caWebApp.Sites[0]
$caWeb = $caSite.RootWeb

$farmAdministrators = $caWeb.SiteGroups["Farm Administrators"]
$farmAdministrators.AddUser($newFarmAdministrator, "", $newFarmAdministrator, "Configured via PowerShell")

$caWeb.Dispose()
$caSite.Dispose()

$caDB = Get-SPContentDatabase -WebApplication $caWebApp
Add-SPShellAdmin -Database $caDB -Username $newFarmAdministrator