You have to create the .ssh directory and the authorized_keys file the first time.
Create the .ssh directory
mkdir ~/.sshSet the right permissions
chmod 700 ~/.sshCreate the authorized_keys file
touch ~/.ssh/authorized_keyschmod 600 ~/.ssh/authorized_keysThe permissions are important! It won’t work without the right permissions!
Now you can add the public key to the authorized_keys file:
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
You have to add the public key of your computer to the authorized_keys file of the computer you want to access using SSH Keys!
As terdon mentioned you can also just use this command:
ssh-copy-id user@host
This will put your id_rsa.pub (in your ~/.ssh directory) in the remote computer’s authorized_keys file, creating the .ssh directory and authorized_keys file with the right permissions if necessary.
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