Debian Linux Post Install Steps

Introduction

Everything on this page needs to be done as root, unless specified, so su to root.

sudo -i

Set hostname

hostnamectl set-hostname sky.mgk.ro
reboot

Update the software

apt update && apt -y upgrade
reboot

Do not install recommended and suggested packages

cat <<EOT >/etc/apt/apt.conf.d/50norecommends
APT::Install-Recommends "false";
APT::Install-Suggests "false"; 
EOT

User management

Create a user (cloud computing)

useradd -c 'Aram Hăvărneanu' -G users -m -s /bin/bash -g staff aram
passwd -l aram

Enable passwordless sudo for the staff group:

echo '%staff ALL=(ALL) NOPASSWD:ALL' > /etc/sudoers.d/91-staff-no-password

Fix the user created during installation (non-cloud)

usermod -a -G staff aram
passwd -l aram

Enable passwordless sudo for the staff group:

echo '%staff ALL=(ALL) NOPASSWD:ALL' > /etc/sudoers.d/91-staff-no-password

SSH

For ssh access, use su to switch from root to the user and then add ssh keys.

su - aram
# as a user
mkdir -p .ssh
echo 'ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIANJ9BKKslS9Zqp1dRWL1nRiLmFp7nGvP06zPJ4L7cES aram@emerald.local' >> .ssh/authorized_keys
echo 'ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJnkro8LT0TS+NTOIB787wfqIwv2VTmXXYsnsoVk71UE aram@horizon.local' >> .ssh/authorized_keys
chmod 700 .ssh
chmod 644 .ssh/authorized_keys