ssh-copy-id Linux | Passwordless SSH

ssh-copy-id is the fastest safe path to passwordless logins — it appends your public key to ~/.ssh/authorized_keys on the server with sane permissions. Still generate keys locally; never copy private keys by email.

Next: harden SSH,
SSH config,
scp & sftp.

Generate a key pair

ed25519 is the modern default; use a passphrase for laptops.

bashkeygen

ssh-keygen -t ed25519 -C "you@laptop" -f ~/.ssh/id_ed25519

Copy key to the server

You will type the password one last time (unless using another auth method).

bashcopy

ssh-copy-id -i ~/.ssh/id_ed25519.pub [email protected]

Test and lock down (carefully)

Confirm key login works in a second session before disabling passwords.

bashtest

ssh -i ~/.ssh/id_ed25519 [email protected] hostname

Permissions matter

OpenSSH ignores authorized_keys if directory permissions are too open.

bashserver perms

chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys

WarningKeep PasswordAuthentication yes until you verify key login from every admin workstation.

Quick Reference

ssh-keygen -t ed25519
ssh-copy-id user@host
Test, then tighten sshd_config

ssh-copy-id on Linux: Passwordless SSH Login (ed25519 Keys)