Cisco :: Create A Bash Script To Log Into Routers And Make Config Changes?

I am trying to create a bash script to log into routers and make config changes.I ran into a snag in that I am unable to pass a password for the ssh login.I tried tying an expect script to handle that piece but was unsuccessful.I saw on google something about public/private ssh keys (not the same type used to ssh into the box) but I do not want to go this route.Can this be done in another language other than a bash script?I would like to avoid TCL or EEM if possible, I want to learn a language that I can use for multiple purposes.