ubuntu setup

(tested with 14.04.1 LTS)

"root" user tab

Login

ssh root@aaa.bbb.ccc.ddd

Update APT

export DEBIAN_FRONTEND=noninteractive
apt-get -qq -y update && apt-get -qq -y dist-upgrade

Add primary user account and restrict logins to that user only

user=cowboy
adduser $user --gecos '' && adduser $user sudo
sed -i.bak -r 's/^(PermitRootLogin) .*/\1 no/;$a\\nUseDNS no\nAllowUsers '$user /etc/ssh/sshd_config
reload ssh

"primary" user tab

Login

ssh aaa.bbb.ccc.ddd

Ensure sudo works

sudo date

Install dotfiles

bash -c "$(curl -fsSL https://bit.ly/cowboy-dotfiles)" && source ~/.bashrc

Copy public key and restrict ssh logins to key-only

sudo cp ~root/.ssh/authorized_keys ~/.ssh/ && \
sudo chown $USER:$USER ~/.ssh/authorized_keys && \
sudo sed -i.bak -r 's/#(PasswordAuthentication) yes/\1 no/' /etc/ssh/sshd_config && \
sudo reload ssh

Verify that everything works

Try to ssh into the server in a new tab. If you can login without a password, your SSH public key is where it needs to be and the "root" user tab may be closed safely. If not, ensure that ~/.ssh/authorized_keys exists and has the correct permissions!

Reference

https://www.digitalocean.com/community/tutorials/initial-server-setup-with-ubuntu-14-04