Generate ssh keys user for authentication, password-less logins, and other things.
ssh-keygen
ssh-keygen -f ~/.ssh/{{filename}}
ed25519
key with 100 key derivation function rounds:ssh-keygen -t ed25519 -a 100
ssh-keygen -t rsa -b 4096 -C "{{email}}"
ssh-keygen -l -F {{remote_host}}
ssh-keygen -l -E md5 -f ~/.ssh/{{filename}}
ssh-keygen -p -f ~/.ssh/{{filename}}