AD binding / password hash.

Hi there, I have a bash script that will help us bind our Macs to AD. In the script there is a field to enter the username and password. I'm ok with putting the username in but not the password and was thinking about using a password hash file but dont know how actually i would call it etc from the script??.. I would then create a pkg (containing the ad bind.sh and password_hash files) and reference this in a catalog file. thanks in advance.