Controlling ssh from an external program

Hi -

I am working on a linux remote administration tool, and I would like to be 
able to control ssh/scp via an external program. I know the standard answer 
to this is to use expect, however this is NOT an option.

The next standard answer is to use an empty passphrase or ssh-agent, but I
cannot guarantee that the remote system will have a keypair, so I need to be
able to fallback on password authentication if that fails. The controlling
program needs to be able to feed the password to ssh/scp.


Additionally, I can only use an unmodified version of openssh (i.e. whatever
version is available on the system that the admin tool is run from).

Any ideas?????


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Jeff Anderson