how I created a ed25519 ssh key

first thing I did was check for available keys on my machine with:

for key in ~/.ssh/id_*; do ssh-keygen -l -f "${key}"; done | uniq

since I only found an RSA key, I did:

ssh-keygen -o -a 100 -t ed25519 -f ~/.ssh/id_ed25519 -C "admin@catman.tech"

the -o saved the private key in the new openssh format (other than pem).

the -a was the number of key derivation function rounds (the higher the slower the passphrase verification).

the -t set the type of key which was ed25519 in this case.

the -f specified the filename of the key being generated.

and finally the -C was a comment of who created the key (not mandatory).

ED25519 is the most recommended public key algorithm at the time of this post.