We’ve shown you how to use SSH to transfer files securely. But there’s a major issue with SSH’s default behaviour. You are only connected with the remote machine after you’ve manually entered the password which rules it out for any tasks you want to run unattended. Or does it?

Here’s a quick lowdown on how the OpenSSH CLI tools (scp and sftp) work so that you can better appreciate the issue. When you want to copy over files to or from the remote host, you can use scp which automatically initiates a SSH connection to the remote host. Every time you run a scp command it establishes a new connection to the remote. So if you have multiple scp commands you’d be entering the same password several times.

This is why you wouldn’t want to use scp in any scripts you want to run unattended. There’s also the fact that if you have multiple accounts on several machines on the network, you’d have trouble memorizing unique, strong passwords for each.

To overcome this problem, you need to switch OpenSSH’s default authentication mechanism to a key-based system.

Full article here:
Run Automated Scripts Over SSH (Make Tech Easier)