Managing SSH keys with ssh-keygen

Generating keys

Generate an Ed25519 key pair (preferred):

ssh-keygen -t ed25519 -f ~/.ssh/id_ed25519

Generate an RSA key pair with passphrase and no prompts:

ssh-keygen -t rsa -f ~/.ssh/id_rsa -N "passphrase"

Generate an RSA key pair with no passphrase and no prompts:

ssh-keygen -t rsa -f ~/.ssh/id_rsa -N ""

Managing keys

Set or change passphrase on an existing key:

ssh-keygen -p -f ~/.ssh/id_rsa

Known hosts

Remove a host from known hosts:

ssh-keygen -R hostname

Visualize known host key fingerprints:

ssh-keygen -lv -f ~/.ssh/known_hosts