Using a text editor, create a file in which to store your private key. This example uses the file private_key.txt.
To edit the file in nano, type the following command
# nano deployment_key.txt
Paste the private key into the file. Be sure to include the BEGIN and END lines.
-----BEGIN RSA PRIVATE KEY----- MIIEowIBAAKCAQEAx9ODcgSZFhPnZmW/VGWy/bXLKFBhOoTP9k4dhcJq17ZuG9KB ... -----END RSA PRIVATE KEY-----
Run the following command to change the file permissions to 600 to secure the key. You can also set them to 400. This step is required:
# chmod 600 deployment_key.txt
Use the key to log in to the SSH client as shown in the following example, which loads the key in file private_key.txt, and logs in as user demo,to IP 18.104.22.168:
# ssh -i private_key.txt firstname.lastname@example.org
When the prompt to confirm the connection request is displayed, type yes and then press Enter.
If your SSH key requires a password, enter it when prompted to complete the connection.