Using Private/Public Key Pair from a Script

Sorry if this is a newb question, that's what I am. I've been browsing the doc but can't find how to completely automate the copy of a file using a private/public key pair rather than password. Using the GUI, I am able to start a session and transfer files. With a script, however, I can't figure out how to tell it the passphrase without user interaction. Can someone give me a pointer to the correct location in the doc to find this info? Thanks MUCH in advance!

I did a bit more searching and found a statment saying that I had to either:

1) Create my private key without a passphrase (seems kind of dangerous)

or

2) Save a session on the client to use using password (passphrase will be prompted if I don't use the password (again seems dangerous)

If there is another way, please let me know. Thanks!

Well, automation is dangerous :-) It's your choice.