I am checking the filename validity on Ubuntu computers. I want to check whether the file extension is correct.

• If the only valid dot is the one before the file extension, then this check is valid:

  
  

  example.endexample -> file extension is endexample
  
  

  
  



• But if a dot is allowed in the filename, then this check is invalid:

  
  

  example.continue.endexample -> file extension is continue.endexample
  
  

  
  

So is separating the value after the first dot in order to get the file extension enough?