Home / Glossary / SSH (Secure Shell)

SSH (Secure Shell)

SFBy Sitraka Forler · Lecturer, Durham Business School·Updated 13 September 2026· About this site

An encrypted way to log in to a remote computer and run commands on it.

You run ssh user@host (port 22 by default) to get an encrypted terminal on a server, and GitHub accepts SSH keys for git push too. Instead of a password you normally use a key pair: the private key stays on your machine and only the public key is copied to the server. Never share or commit the private key: anyone who has it (plus its passphrase, if set) can log in wherever the matching public key is installed.

# saves ~/.ssh/id_ed25519 (private) and id_ed25519.pub (public)
ssh-keygen -t ed25519 -C "you@example.com"
# copies that public key to the server
ssh-copy-id -i ~/.ssh/id_ed25519.pub user@server.example.com
# log in (port 22 by default)
ssh user@server.example.com