SSH — trusting the server and logging in with a key

Articles

• journalctl — reading the systemd journal — Command for reading the systemd journal with service, time, and other filters.
• ssh, scp — connecting and copying over SSH — A client for logging in and copying files over SSH; host aliases in ~/.ssh/config remove repeated connection parameters.
• SSH keys and ssh-agent — Key pairs for passwordless login; sshd rejects ~/.ssh if it is writable by the group or by others.
• ssh-keyscan — collecting host keys — Pre-populate known_hosts with server keys — skip the interactive "yes" on first ssh.
• chmod / chown — permissions and ownership — Changing permissions (chmod) and owner/group (chown) — numeric and symbolic syntax, umask, chgrp.
• sshd — the SSH server — The OpenSSH server; edit the config with a second session open — a mistake in PermitRootLogin locks you out immediately.