SSH · Secure Shell
/ ess-ess-AYCH /
SSH — Secure Shell — is the standard way to log into another computer over the network and run commands on it as if you were sitting right there. It's how you reach a server in a data center halfway around the world from your own laptop.
The 'secure' is the whole point: everything between you and the remote machine is encrypted, so nobody listening on the network can read your commands, your password, or the data coming back. The older tools it replaced sent everything in plain text — a genuinely bad idea.
Instead of typing a password every time, most people use a key pair: a private key that stays secret on your machine, and a public key you put on the server. The two match up to prove it's really you — quietly, in a fraction of a second, every time you connect.
$ ssh [email protected] [email protected]'s machine — last login: Mon 09:12 $
Connect to a remote server as the 'deploy' user — now the prompt is theirs, not yours.
The 'd' daemon that listens for these connections on the far end is called sshd — the server half of SSH, always quietly waiting for you to knock.