You might tell us how the code fails for you, and on what input, and what output you get.

__DATA__ <script type="java/js"> foobie bletch </script> <%-- <script> zelgo mer </script> --> input is same as temporal used.but when i'm executing this code it's not able to make changes in file.i'm using .txt file

temporal used the __DATA__ segment to avoid the need for an external file. You will need to learn how to open a file for reading and then read it in like temporal's code does. The code does not modify a file but it creates output that could be written to a new file. You will have to learn how to open a file for writing, too.