I've been hesitating for a couple months about whether to mention sshpass. Conceptually, it's a horrible, horrible program. It basically allows you to enter an SSH user name and password on the command line, so you can create a connection without any interaction. A far better way to accomplish that is with public/private keypairs. But it's still something I find useful from time to time, and I'd rather mention it with all the warnings in the world than to pretend it doesn't exist.

So, sshpass—it's a simple tool, but in a pinch, it can be incredibly helpful. You use it with the user name and password as command-line arguments (with some variations, see the help screen in the screenshot), and it injects them into your ssh (or scp) command.

Again, this is a horribly insecure method for entering passwords. However, I find it particularly useful for setting up new machines, especially computers or devices in a closed environment. I've also used it to send files via scp to hundreds of machines in my local network that I'll never need to connect to again. It's a dangerous tool, but can be a lifesaver if you need it. Search your distribution's repositories, as it's available for most systems. And remember, don't ever use it!