kazulog@sv1:~$ ssh-copy-id taro@localhost
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/home/kazulog/.ssh/id_ed25519.pub"
The authenticity of host 'localhost (::1)' can't be established.
ED25519 key fingerprint is: SHA256:vDLOqQp6GgOzTjPqeoR46WuIvZDNbZwA6yCtoqLsv/A
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
taro@localhost's password:

Number of key(s) added: 1

Now try logging into the machine, with: "ssh 'taro@localhost'"
and check to make sure that only the key(s) you wanted were added.

kazulog@sv1:~$ sudo ls -la /home/taro/.ssh/
total 12
drwx------ 2 taro taro 4096 Sep 10 14:50 .
drwxr-x--- 4 taro taro 4096 Sep 10 14:50 ..
-rw------- 1 taro taro   96 Sep 10 14:50 authorized_keys
kazulog@sv1:~$ sudo cat /home/taro/.ssh/authorized_keys
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIEMqxsy1w3cy075/v+S2ltHfVQOMZIYrE7yBHCwiqhUT kazulog@client