Oracle: UTL_FILE.FGETATTR

declare
   exs    boolean;
   len    number;
   bls    binary_integer;
begin
   utl_file.fgetattr(
      location    => 'EXT_DIR',
      filename    => 'file.csv',
      fexists     =>  exs,
      file_length =>  len,
      block_size  =>  bls
   );

   if exs then
      dbms_output.put_line('file length: ' || len);
      dbms_output.put_line('block size:  ' || bls);
   else
      dbms_output.put_line('file does not exist');
   end if;

end;
/