Set-ADAutoGroupMembership.ps1

function Set-ADAutoGroupMembership{
    <#
    .SYNOPSIS
        Add users from an OU path into a security group
    .DESCRIPTION
        Schedule this script to run at a recurring time to automatically add users from an OU path to a group.

        This is useful for other areas of the network that depend on security group to determine access .
    .PARAMETER Level
        A Base query searches only the current path or object.
        A OneLevel query searches the immediate children of that path or object.
        A Subtree query searches the current path or object and all children of that path or object.
    #>
    Param(
        # Distinguished name path to find users.
        [Parameter(Mandatory=$true)]
        [string]
        $SearchBase

        , # Search Scope level to find users
        [string]
        [ValidateSet('Base', 'OneLevel', 'Subtree')]
        $Level = 'Subtree'

        , # Security group to add members to
        [Parameter(Mandatory=$true)]
        [string]
        $TargetGroup

        , # Rule to filter the user search quiery with
        [string]
        $filter = "ObjectClass -eq 'user'"

        , # Host computer to import powershell ActiveDirectory module cmdlets from. Defaults to first domain controller
        [string]
        $ModuleSource = ([DirectoryServices.ActiveDirectory.Domain]::GetCurrentDomain().domainControllers[0].name)
    )
    try {
        write-verbose "Import the activeDirectory module from: $ModuleSource"
        import-module ActiveDirectory -pssession (new-PSSession $ModuleSource) -ErrorAction stop
    }catch {
        throw $error[0]
    }
    try{
        write-verbose "Get group: $TargetGroup"
        $group = get-adgroup $TargetGroup -ErrorAction Stop
    } catch {
        write-Error "Missing group: $TargetGroup"
        throw $error[0]
    }
    write-verbose "Get Members at path: $SearchBase"
    $members = get-aduser -filter $filter -SearchBase $SearchBase -SearchScope $level -ErrorAction Stop -ResultSetSize $null

    write-verbose "total Members to add: $($members.count)"
    Add-ADGroupMember -Identity $group.DistinguishedName -Members $members.DistinguishedName
}