$ sshkey-gen -t ed25519 -C ""

Generating public/private ed25519 key pair.
Enter file in which to save the key (/home/michiya/.ssh/id_ed25519): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/user/.ssh/id_ed25519.
Your public key has been saved in /home/user/.ssh/id_ed25519.pub.
The key fingerprint is:
*******************************
The key's randomart image is:
+--[ED25519 256]--+
*******************
*******************
*******************
*******************
*******************
*******************
*******************
*******************
+----[SHA256]-----+

-Cを指定しない場合，コメントとして公開鍵にuser@hostnameが記載されるため，気になる場合は-C ““でコメントを空白を指定することで記載されない．