Set-CustomACL.ps1

function Set-CustomACL {
    <#
    .SYNOPSIS
    Sets a Custom ACL on a provided folder
    
    .DESCRIPTION
    Sets ACl permissions on a provided folder recursively
    
    .PARAMETER User
    The user to add to the ACL
    
    .PARAMETER Rights
    FilesystemRights to grant to the user account. You can use Get-Help Set-CustomACL to see valid values
    
    .PARAMETER ACLType
    The ACL Type to provide to the user - Valid values are:
    Allow, Deny
    
    .PARAMETER StartingDir
    Directory on which to set the ACL permissions
    
    .EXAMPLE
    Set-CustomACL -User "domain\Brettm" -Rights FullControl -ACLType Allow -StartingDir C:\Temp

    .EXAMPLE
    Set-CustomACL -User "domain\Brettm" -Rights ReadAndExecute, ReadAttributes, CreateDirectories, CreateFiles -ACLType Allow -StartingDir C:\Temp
    
    .NOTES
    General notes
    #>
    [CmdletBinding()]
    param (
        [System.Security.Principal.NTAccount]$User,
        [System.Security.AccessControl.FileSystemRights]$Rights = "FullControl",
        [System.Security.AccessControl.AccessControlType]$ACLType = "Allow",
        
        [Parameter(Mandatory)]
        [ValidateScript({Test-Path -Path $_ -PathType Container})]
        $StartingDir
    )
    
    begin {
        $rule = New-Object System.Security.AccessControl.FileSystemAccessRule(
            $User,
            $Rights,
            $ACLType
        )
    }
    
    process {
        foreach ($file in (Get-ChildItem $StartingDir -recurse)) {
            $acl = Get-Acl -Path $file.FullName
            
            #Add this access rule to the ACL
            $acl.SetAccessRule($rule)
            
            #Write the changes to the object
            Set-Acl $File.Fullname $acl
        }
    }
}