open(FH, "+< FILE") or die "Opening: $!";
   @ARRAY = <FH>;
   # change ARRAY here
   seek(FH,0,0)           or die "Seeking: $!";
   print FH @ARRAY        or die "Printing: $!";
   truncate(FH,tell(FH))  or die "Truncating: $!";
   close(FH)              or die "Closing: $!";