Powershell script to compare AD ComputerObject Group Memberships in Excel

<#
CompareComputerGroupMembershipsFromList.ps1
Powershell script to compare AD ComputerObject Group Memberships in Excel
[string](0..9|%{[char][int](32+("45737569004673677976").substring(($_*2),2))})-replace "\s{1}\b"
save list.txt file in same directory as script with ComputerNames (one per line), example follows:

comp1
comp2
comp3
comp4

#>
cls
function vars { get-variable | sort Name }
vars | remove-item #-whatif
$erroractionpreference = "SilentlyContinue"
Import-Module ActiveDirectory
$currentfolder = split-path $myinvocation.mycommand.path
$groups = ""
$computerlist = GC $currentfolder\list.txt | sort
if (test-path $currentfolder\temp.txt) {remove-item $currentfolder\temp.txt}
if (test-path $currentfolder\MasterGroupList.txt) {remove-item $currentfolder\MasterGroupList.txt}
if (test-path $currentfolder\computerCNs.txt) {remove-item "$currentfolder\computerCNs.txt"}

Foreach ($node in $computerlist)
    {
        $array = @() 
        $groups = Get-AdComputer -Identity $node -property "MemberOf" 
        $sortedGroups = $groups.memberof | Sort | Get-Unique
            Foreach($group in $sortedGroups) 
            {$array +=$group} 
        $number = $array.count
        foreach ($item in $array)
        {      
         $1 = $item -replace "CN\=","" 
         $2 = $1 -replace "^*,OU\=.*$","" 
         add-content $currentfolder\temp.txt $2    
        }  
    }
$MasterGroupList = gc $currentfolder\temp.txt | sort | Get-Unique
remove-item $currentfolder\temp.txt
foreach ($schlub in $MasterGroupList) 
{add-content $currentfolder\MasterGroupList.txt $schlub}
# some Excel Constants 
# line styles 
$xlLineStyleNone = -4142 
$xlContinuous = 1 
$xlDash = -4115 

$a = New-Object -comobject Excel.Application
$a.Visible = $true
$b = $a.Workbooks.Add()
$WS=$a.ActiveSheet
$cells = $WS.Cells
$date = Get-Date

#define some variables to control navigation
$row=1
$col=2
        $WS.UsedRange.Borders.LineStyle = $xlContinuous
        $blue = 255
        $green= 0
        $red = 0
        $a = 1
        $WS.UsedRange.Borders.Color = $a
        $WS.UsedRange.Borders.Weight = $xlThin
        $WS.Application.ActiveWindow.SplitColumn = 1
        $WS.Application.ActiveWindow.SplitRow = 1
        $WS.Application.ActiveWindow.FreezePanes=$true 
#insert column headings
GC $currentfolder\MasterGroupList.txt | foreach {
        $cells.item($row,$col)=$_
        $cells.item($row,$col).font.bold=$False
        $cells.item($row,$col).Orientation = 90
        $cells.EntireColumn.AutoFit() | Out-Null
        $WS.UsedRange.Borders.LineStyle = $xlContinuous
        $col++
    }
$row=2
$col=1
$blarb = Get-Content ("$currentfolder\list.txt") | Sort | Get-Unique
foreach ($slarb in $blarb)
    {   
        $CN = Get-AdComputer -Identity $slarb 
        Add-Content "$currentfolder\computerCNs.txt" $CN
    }
$GroupList = @{} 
Function IsMember ($ADObject, $GroupName) 
    { 
        If ($GroupList.ContainsKey($ADObject.sAMAccountName.ToString() + "\") -eq $False) 
        { 
            $GroupList.Add($ADObject.sAMAccountName.ToString() + "\", $True) 
            $ADObject.psbase.RefreshCache("tokenGroups") 
            $SIDs = $ADObject.psbase.Properties.Item("tokenGroups") 
            ForEach ($Value In $SIDs) 
            { 
                $SID = New-Object System.Security.Principal.SecurityIdentifier $Value, 0 
                $Group = $SID.Translate([System.Security.Principal.NTAccount]) 
                $GroupList.Add($ADObject.sAMAccountName.ToString() + "\" + $Group.Value.Split("\")[1], $True) 
            } 
        } 
                If ($GroupList.ContainsKey($ADObject.sAMAccountName.ToString() + "\" + $GroupName)) {Return $True} 
                Else {Return $False } 
    } 
     $computerCNs = Get-Content("$currentfolder\ComputerCNs.txt") 
     foreach ($item in $computerCNs) 
        {  
            $Computer = [ADSI]"LDAP://$item" 
            $3 = $item -replace "CN\=","" 
            $4 = $3 -replace "^*,OU\=.*$",""
            $x=1
            $y=2
                   foreach ($habba in Get-content $currentfolder\MasterGroupList.txt)
                            {
                             If (IsMember $Computer $habba -eq $True) 
                                 {  write-host Yes,$habba,$Computer.sAMAccountName -Foregroundcolor green
                                    $cells.item($row,$col)=$4
                                    $cells.EntireColumn.AutoFit() | Out-Null
                                    $cells.item($row,$col).font.bold=$True
                                    $WS.Cells.Item($row,$y).Value() =1;$WS.Cells.Item($row,$y).Interior.ColorIndex = 34 
                                 }
                             Else
                                 {
                                    write-host No,$habba,$Computer.sAMAccountName -Foregroundcolor red
                                 }
                              $y++
                              $WS.UsedRange.Borders.LineStyle = $xlContinuous        
                            }
                   $Row++
         } 
if (test-path $currentfolder\MasterGroupList.txt) {remove-item $currentfolder\MasterGroupList.txt}
if (test-path $currentfolder\computerCNs.txt) {remove-item "$currentfolder\computerCNs.txt"}

 
  Function Convert-NumberToA1 
    { 

      Param([parameter(Mandatory=$true)] 
            [int]$number) 
 
      $a1Value = $null 
      While ($number -gt 0) { 
        $multiplier = [int][system.math]::Floor(($number / 26)) 
        $charNumber = $number - ($multiplier * 26) 
        If ($charNumber -eq 0) { $multiplier-- ; $charNumber = 26 } 
        $a1Value = [char]($charNumber + 64) + $a1Value 
        $number = $multiplier 
      } 
      Return $a1Value 
    }
  # End Function
 
Function xlSum 
        {
                $range = $WS.usedRange
                $rows  = $range.rows.count # Takes you to the last used row
                $cols   =  $range.columns.count # Takes you to the last used column
                $Sumrow = $rows + 1
                $Sumcol  = $cols + 1
                $Q=2
                $U=2
                        do
                            {
                                $Y=2
                                $p =  Convert-NumberToA1 ($Q)
                                $r = ("" + $p + $Y + ":" + $p + $rows)
                                write-host range $r
                                $derp = $WS.Range($r) 
                                write-host $Q$Sumrow
                                $WS.cells.item($SumRow,$Q) = $functions.sum($derp)
                                [void]$range.entireColumn.Autofit()
                                $Q++
                             }
                    while($Q -lt $Sumcol)
                        do
                            {
                                $G =  Convert-NumberToA1 ($cols)
                                $r = ("" + "B" + $U + ":" + $G + $U)
                                write-host range $r
                                $derp = $WS.Range($r) 
                                write-host $U$SumCol
                                $WS.cells.item($U,$Sumcol) = $functions.sum($derp)
                                [void]$range.entireColumn.Autofit()
                                $U++
                             }
                    while($U -lt $Sumrow)
                $WS.cells.item($SumRow,$SumCol) = $functions.sum($range)
                $cells.EntireColumn.AutoFit() | Out-Null
        } 
# End Function
        xlSum 
 #End Script