PowerShell :: Display AD Group Membership Hierarchy

#requires –Modules ActiveDirectory -version 3.0

clear-host

#NB: currently assumes that all users & groups are in the same domain
function Get-AdGroupHierarchy {
    [cmdletbinding()]
    param(
        [parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [string]$AdGroupSamAccountName
        ,
        [parameter(Mandatory = $false)]
        [int]$Level = 0
        ,
        [parameter(Mandatory = $false)]
        [string]$DisplayField = 'SamAccountName' #allows us to use names instead of samAccountNames if desired; though faster if we just use the sAmAccountName as avoids a lookup per call
        ,
        [parameter(Mandatory = $false)]
        [switch]$IncludeManagedBy 
    )
    begin {
        [string[]]$DefaultDisplayProperties = @('Directory')
        if($IncludeManagedBy){
            $DefaultDisplayProperties += 'ManagedBy'
        }
    }
    process {
        [string]$managedBy = ''
        [string]$displayName = $AdGroupSamAccountName
        if(($DisplayField -ne 'SamAccountName') -or ($IncludeManagedBy)) { #save an ad lookup if not required
            $group = Get-AdGroup $AdGroupSamAccountName -Properties ManagedBy, $DisplayField 
            $displayName = $group | Select-Object -ExpandProperty $DisplayField
            if (($IncludeManagedBy) -and ($group.ManagedBy)) {
                $managedBy = $group.ManagedBy | Get-AdUser -Properties DisplayName | Select-Object -ExpandProperty DisplayName
            }
        }
        (new-object -TypeName PSObject -Property ([ordered]@{
            Level = $Level
            DisplayName = $DisplayName
        })) `
        | %{if($IncludeManagedBy){$_ | Add-Member -MemberType NoteProperty -Name ManagedBy -Value $managedBy -PassThru}else{$_}} `
        | Add-Member -MemberType ScriptProperty -Name DirectorySpacer -Value {("`t" * $this.Level) + ('|- ' * ($this.Level -gt 0))} -PassThru `
        | Add-Member -MemberType ScriptProperty -Name Directory -Value {$this.DirectorySpacer + $this.DisplayName} -PassThru `
        | Add-Member -MemberType MemberSet -Name PSStandardMembers -Value ([System.Management.Automation.PSMemberInfo[]](New-Object System.Management.Automation.PSPropertySet DefaultDisplayPropertySet, $DefaultDisplayProperties)) -PassThru
        Get-AdGroupMember $AdGroupSamAccountName | ?{$_.objectClass -eq 'group'} | Select-Object -ExpandProperty SamAccountName | Sort-Object | Get-AdGroupHierarchy -Level ($level + 1) -DisplayField $DisplayField -IncludeManagedBy:$IncludeManagedBy
    }
}

Get-AdGroupHierarchy 'MyAdGroupSamAccountName' #see just the directory structure
Get-AdGroupHierarchy 'MyAdGroupSamAccountName' -IncludeManagedBy | ft -AutoSize #see directory structure and manager
Get-AdGroupHierarchy 'MyAdGroupSamAccountName' -IncludeManagedBy | select * #see all properties being returned