SSH Setup

SSH authentication lets you push and pull without entering your password every time. It uses a key pair — a private key on your machine and a public key registered with your Git host.

1. Generate a key

$ ssh-keygen -t ed25519 -C "you@example.com"

Accept the default file location (~/.ssh/id_ed25519). Set a passphrase for extra security, or press Enter to skip.

2. Start the SSH agent and add the key

$ eval "$(ssh-agent -s)"
$ ssh-add ~/.ssh/id_ed25519

On macOS, add --apple-use-keychain to persist the key across reboots.

3. Register the public key with GitHub

Copy the public key to your clipboard:

$ cat ~/.ssh/id_ed25519.pub

Then go to GitHub > Settings > SSH and GPG Keys > New SSH Key, paste the key, and save.

4. Verify the connection

$ ssh -T git@github.com

You should see a message like “Hi username! You’ve successfully authenticated.”

5. Switch an existing remote from HTTPS to SSH

$ git remote set-url origin git@github.com:<user>/<repo>.git

Troubleshooting

Permission denied (publickey) — the agent does not have the key loaded. Run ssh-add again.
Wrong key used — if you have multiple keys, create an ~/.ssh/config entry to map the host to the correct key file.
Firewall blocks port 22 — use SSH over HTTPS port: ssh -T -p 443 git@ssh.github.com.