You would be much better off by installing and using something like sudo which will allow you to do things like this (in a controlled and regulated manner) without using passwords. I am willing to bet that your script has read permissions for all others and I am certain that ashok loves it that everyone can read his password (if they know where to find the script).
You really should not be passwords and/or passphrases in scripts. Like I said use "sudo", or something similar. Google for and download it, if it is not already installed. If you are using some form of Linux, I can would bet that it already is installed.
subject: Problem with su - user_name inside script