How to append authorized_keys on the remote server with id_rsa.pub key

How to append authorized_keys on the remote server with id_rsa.pub key from the local machine with a single command?

ssh-copy-id user@remote_server

http://linux.die.net/man/1/ssh-copy-id

Adding an authorized key could be one-lined this way (use double-quotes so it's interpreted before sent):

ssh user@server "echo \"`cat ~/.ssh/id_rsa.pub`\" >> .ssh/authorized_keys"

This does the trick:

cat ~/.ssh/id_rsa.pub | (ssh user@host "cat >> ~/.ssh/authorized_keys")

Appends the local public key the remote authorized_keys file.

The ssh-copy-id program is the standard way but the key can be appended manually to the ~/.ssh/authorized_keys file:

cat ~/.ssh/id_rsa.pub | ssh username@host "mkdir ~/.ssh; cat >> ~/.ssh/authorized_keys"

This does not check if the key already exists and can lead to duplicates.

The most convenient option is the ssh-copy-id command. It can append the public key to ~/.ssh/authorized_keys. For example:

ssh-copy-id -f -i id_rsa.pub username@host

Where:

• -f: force mode -- copy keys without trying to check if they are already installed
• -i: [identity_file]