$ curl cheat.sh/
# ssh-keyscan
# Get the public ssh keys of remote hosts.
# More information: <https://man.openbsd.org/ssh-keyscan>.

# Retrieve all public ssh keys of a remote host:
ssh-keyscan host

# Retrieve all public ssh keys of a remote host listening on a specific port:
ssh-keyscan -p port host

# Retrieve certain types of public ssh keys of a remote host:
ssh-keyscan -t rsa,dsa,ecdsa,ed25519 host

# Manually update the ssh known_hosts file with the fingerprint of a given host:
ssh-keyscan -H host >> ~/.ssh/known_hosts

$
Follow @igor_chubin cheat.sh tldr