To enable login to a remote machine by ssh without having to enter the password is a useful thing, and one I get asked about with some regularity. I'll describe two methods I use, one that uses ssh public keys with no passphrases, and the other using ssh-agent to store the passphrases of your keys.

To use ssh keys, you'll first need to have one. You can create this with the ssh-keygen utility like so:

ssh-keygen -t <algorithm> -b <bit size>

for example:

ssh-keygen -t rsa -b 4096