passwordless ssh login into remote server

passwordless_ssh.sh

# either use existing authentication keys, check with:
ll ~/.ssh/id_*
# if none exist that can be reused, 
# or generate a new key with
ssh-keygen -t rsa
# which will automatically generate private/public keys as ~/.ss/id_*[.pub]
# check again with
ll ~/.ssh/id_*
# copy the public key to the remote server with; by default, this will copy the most recent 
# key to the remote server, if that is not the case, use the '-i' option
ssh-copy-id remote_username@server_remote_name_or_ip_address
# check that the public key was appended on the remote server in ~/.ssh/authorized_keys
# now passwordless login should work
# if it does not, check that on the remote (an probably on the local as well) the following is true
chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys
# moreso, check also that the following is true on the remote (and probably on the local as well)
chmod go-w ~


# Reference:
# - https://www.techjunkie.com/ssh-login-without-key-password/
# - https://stackoverflow.com/questions/6377009/adding-a-public-key-to-ssh-authorized-keys-does-not-log-me-in-automatically