title: Compare two .CSV files and output the duplicate names
body: <p>I'm new to Powershell, and the title pretty much points out what I'm trying to do. I have here two .CSV files that includes the usernames of a group and the other an OU. I need to compare the userlist of the group and the OU then proceed with deleting the duplicates from the group in AD.</p>
  
  <p>I've been googling around, and have found a few leads, but me being a new Powersheller I have not been able to combine what I've found into a working command that does what I want it to.</p>
  
  <p>Here is the format of the .CSV files that I want to be compared. Samaccountname (the header) should not be compared.</p>
  
  <pre>
  "samaccountname"
  "tb2"
  "tb3"
  "tb4"
  </pre>