Find all unique file owners through Powershell in an NTFS file system

Question

I'm trying to find all unique file owners in an NTFS file system. Getting the number is fairly straightforward, but my current approac is very inefficient:

$Shares = @( "\\Server\Share1", "\\Server\Share2", "\\Server\Share3", "\\Server2\Share1", ... ) $i = 0 foreach ($Share in $Shares) { $i++ $AllFiles = Get-ChildItem -Path $Share -File -Recurse -Force -ErrorAction SilentlyContinue $Output = $AllFiles | ForEach-Object { [System.IO.FileSystemAclExtensions]::GetAccessControl($_).Owner } | Group-Object | Sort-Object Name | Select-Object Count, Name $Output | Out-File "C:\My Path\My file$i.csv" } 

I don't think there's any way around using [System.IO.FileSystemAclExtensions]::GetAccessControl() but is there some better, more efficient way of getting the unique file owners only? There are two issues I can see here:

1. Storing the file info of every single file in the share in a single variable
2. Running a Group-Object command on that massive data set

I thought about instead of using Group-Object storing them in a separate ArrayList and for each file see if the owner already exists but then I'd have to compare an increasingly large ArrayList with a value every time, so that feels like it would be exponentially slower than doing the Group-Object approach.

Are there better options doing this?

Answer 1

If you only care about the unique file owners (not the count), something like (not fully fleshed out but to give you an idea):

function Get-UniqueOwners([String]$Path) { $GciArgs = @{ LiteralPath=$Path; Recurse=$True; Force=$True; ErrorAction='SilentlyContinue'; } $Owners = New-Object System.Collections.Generic.HashSet[String] foreach ($file in Get-ChildItem @GciArgs | Where-Object {! $_.PSIsContainer}) { #"File: '{0}'" -f $file.FullName [void]$Owners.Add($file.GetAccessControl().Owner) } $Owners } $Shares = @( "\\Server\Share1", "\\Server\Share2", ) foreach ($Share in $Shares) { "Scanning '{0}'" -f $Share Get-UniqueOwners $Share "" } 

Edit: or to get the owner count

function Get-OwnerCount([String]$Path) { $GciArgs = @{ LiteralPath=$Path; Recurse=$True; Force=$True; ErrorAction='SilentlyContinue'; } $Owners = @{} foreach ($file in Get-ChildItem @GciArgs | Where-Object {! $_.PSIsContainer}) { $Owners[$file.GetAccessControl().Owner]++ } $Owners }