How do you do this with local programs? Why do you think that remote programs will be any different? Just remember: ssh is, itself, a local program. Treat it as such, and you may find things are much simpler.

If you use open("| localprogram") to write to a local program, just use open("|ssh xxx.xxx.xxx.xxx -l user 'shell script that needs input'") to run the local program of 'ssh'.

(PS: you should respond sooner ... as you notice, most new topics get responses fairly quickly - 12 days is more than enough time for responses. In fact, if you don't have a response within 24 hours, chances of getting any responses goes way down.)