#ssh

Skip the manual cat >> authorized_keys dance — ssh-copy-id pushes your public key to a server and fixes permissions in one shot.

Windows has shipped a full OpenSSH client since 1809 — no PuTTY needed for everyday SSH.

Push or pull files and whole directories between machines using cp-like syntax over an encrypted SSH channel.

Load your passphrase-protected SSH key into the agent so git push and ssh connect without re-typing the passphrase.

One of the first hardening steps: no more direct root connections from the internet.

Forward a local port through SSH to a service on the remote machine — reach dev servers and databases behind firewalls without exposing them.

Apple's ssh-add has a macOS-specific flag, --apple-use-keychain, that remembers passphrases so ssh-agent can load keys automatically.

The OpenSSH agent exists on Windows but ships disabled — three PowerShell lines make passphrases painless.

systemsetup -setremotelogin enables the macOS SSH server so you can log in from another machine.

Set owner-only permissions on your SSH private key with chmod 600 so ssh will use it and other users can't read it.

Transfer a file to another machine over SSH with one command.

Copy files to and from a server through the encrypted SSH File Transfer Protocol.