Install public key via ssh-copy-id for other users

Question

ssh-copy-id can be used to install your public key in a remote machine's authorized_keys. Could the same command be used to install other users' public keys, if you have sudo ability?

Update: both local and remote are using Ubuntu 12.04.

Update 2: describing the procedure of creating a new user account and adding public key

1. (remote) Create a new user account, and set it to user public key access only.
2. (local) Generate a public key for the new user account (ssh-keygen).
3. Normally I do is to create the directory and file .ssh/authorized_keys on the remote server, then copy and paste the public key generated locally to the new user's account. What I am looking for is that if I can use ssh-copy-id to install this newly created user's public key directly into the ssh directory. Just to save a couple more commands.

Answer 1

Not the same command but if you have sudo on the remote host, you can use ssh to remotely do the required steps. I use the following command to push my ssh key to my raspberry's root user:

cat ~/.ssh/id_rsa.pub | \
  ssh pi@192.168.1.25 \
  "sudo mkdir /root/.ssh; sudo tee -a /root/.ssh/authorized_keys"

• cats my bublic key
• pipes it to ssh
• ssh connects to my raspberry as ssh user
• on remote uses sudo to create /root/.ssh
• then uses sudo with "tee -a" to append stdin (which holds the key from first cat) to /root/.ssh/authorized_keys

Just put this stuff together as a script, maybe add some chmod/chown on the remote side and you have what you need.

Answer 2

Yes :), If you, for example, are logged as ghost@ubuntu and you

ssh-copy-id root@host-ip

Than you will see, on host server in /root/.ssh/authorized_keys file key ending with ghost@ubuntu.
That means that ghost user has copied his key pair and doesn't have to type in password anymore.
I'm not sure it will work with -u <username> flag now, but you can always log as different user with

su <user_name> 

and then ssh-copy-id ...