$userInput = <STDIN>;
chomp $userInput;
$userInput = uc $userInput; 
# you could probably do this on the STDIN, but I am not sure.
# Another monk should be able to tell you.

    ( $userInput eq 'L' or $userInput eq 'LIST'  ) ? list_phone_book()
  : ( $userInput eq 'A' or $userInput eq 'ADD'   ) ? add_to_phone_book()
  : ( $userInput eq 'D' or $userInput eq 'DELETE') ? delete_from_phone_book()
  : ( $userInput eq 'Q' or $userInput eq 'QUIT'  ) ? quit_phone_book()
  :                                                  unknown_selection();