Removing ALL user object permissions form ACL / Folder structure - powershell

Question

I want to remove ALL AD User objects from a directory/folder security.
So, this maybe a stupid post and i appologise if it is...but basically i want to recurse through a directoery and remove all user objects from permissions. Folder permissions should be secured using groups, buit occasionally there are user onjects directly being added to folders breaking the rules. I've got a simple little script that works great for specific users, but i'm having trouble setting this to use a variable, eg all domain user accounts. If i specify the $user variable as an AD search for instance it just doesnt work, eg $USER = 'Get-ADuser -filter * -Server 'DOMAIN -properties SamAccountName | Select SamAccountName
I'm assumign this doesnt like the variable field set this way. Any help or advise much appreciated. Thanks.
$filepath = 'C:\Temp\ACLTesting'
$user = 'DOMAIN\USER'
Get-ChildItem $filePath -Recurse -Directory | ForEach-Object {
$acl = Get-Acl -Path $_.FullName
$acl.Access | Where-Object {
$_.IdentityReference.Value -eq $user
} | ForEach-Object {
$acl.RemoveAccessRule($_) | Out-Null
}
Set-Acl -Path $_.FullName -AclObject $acl
}
Unfortunately still cant get this to work using user variables... am i missing something or is this not a possible function? Thanks....
Putting this to one side for now as still cant get it to work and other things have cropped up to look at. Will revisit this at somepoint though. Any suggestions always welcome. Thanks.

Answer 1

Slightly modifying what you posted, try this …
$filepath = 'C:\Temp\ACLTesting'
$DomainUsers = (Get-ADUser -Filter *).SamAccountName
ForEach ($DomainUser in $DomainUsers)
{
Get-ChildItem $filePath -Recurse -Directory |
ForEach-Object {
$acl = Get-Acl -Path $_.FullName
$acl.Access |
Where-Object {
$_.IdentityReference.Value -eq $DomainUser
} |
ForEach-Object {
$acl.RemoveAccessRule($_) | Out-Null
}
Set-Acl -Path $_.FullName -AclObject $acl
}
}