Compare Permissions of two folders at different locations - powershell

Question

I m trying to write a script to compare permissions of two folders at two different locations. The Folder name at both locations would be the ADID of an user and some users may have two or more AD accounts.
$OutPath = ".\out1.csv"
$sourcepath1 = Get-Content ".\mwd_src.txt"
foreach ($path1 in $sourcepath1) {
$name1 = (Get-Item $Path1).name
$FolderAcl1 = (Get-Acl $Path1).Access | Select-Object IdentityReference
$Source = $FolderAcl1 | Where-Object { $_.IdentityReference -like "*$name1*"} |
Select-Object #{ Label = "Path"; Expression = { echo $Path1 } }, #{ Label = "Access"; Expression = { $_.IdentityReference } }
}
$sourcepath2 = Get-Content ".\mwd_dest.txt"
foreach ($path2 in $sourcepath2) {
$name2 = (Get-Item $Path2).Name
$FolderAcl2 = (Get-Acl $Path2).Access | Select-Object IdentityReference
$Dest = $FolderAcl2 | Where-Object { $_.IdentityReference -like "*$name2*" } |
Select-Object #{ Label = "Path"; Expression = { echo $Path2 } }, #{ Label = "Access"; Expression = { $_.IdentityReference } }
}
$Source1 = $Source | Select-Object -Unique
$Dest1 = $Dest | Select-Object -Unique
$Out = Compare-Object -ReferenceObject $Source1 -DifferenceObject $Dest1
$Out1 = $Out | Where-Object { $_.SideIndicator -match "=>" }
foreach($OutItem in $Out1) {
$Outitem.InputObject | Add-Content $OutPath
}
But getting the following error
"Compare-Object : Cannot bind argument to parameter 'DifferenceObject' because it is null.
"
Please assist.

Answer 1

As I am missing information to your paths, I cannot reproduce your code but I tried to compare the ACLs for two local files with Compare-Object. I create two files which initially had the same accesses. If there is no difference, nothing is returned. I removed my account then from the permissions of the second file and got the output. (I shortened the output to avoid a horizontal bar.) The SideIndicator shows with the arrow to which object the difference belong.
InputObject SideIndicator
----------- -------------
{System.Security.AccessControl.FileSystemAccessRule, System.Security... =>
{System.Security.AccessControl.FileSystemAccessRule, System.Security... <=
My test code:
$ref = Get-Acl -Path .\Desktop\test1.txt
$diff = Get-Acl - Path .\Desktop\test2.txt
Compare-Object -ReferenceObject $ref.Access -DifferenceObject $diff.Access
I selected the Access property for comparison.
Regarding your error, ensure that the DifferenceObject is populated with the information you expect.