VPS Quick setup

install.sh

#!/bin/sh

# The idea behind this script is to setup a non root user to act as the main admin, allow use of sudo
# and set up SSH keys

# Function to add a user and configure sudo access
add_admin_user() {
    read -p "Enter the admin username: " username
    echo "Admin username: $username"

    while true; do
        read -s -p "Enter the admin password: " password
        echo
        read -s -p "Confirm the admin password: " password_confirm
        echo

        if [ "$password" != "$password_confirm" ]; then
            echo "Passwords do not match. Please try again."
        else
            break
        fi
    done

    # Create the admin user
    useradd -m "$username"

    # Set the admin user's password
    echo "$username:$password" | chpasswd

    # Determine sudo group based on the distribution
    if command -v dpkg &> /dev/null; then
        sudo_group="sudo"
    elif command -v rpm &> /dev/null; then
        sudo_group="wheel"
    else
        echo "Unsupported distribution. Manually configure sudoers."
    fi

    # Add the user to the sudo or wheel group
    usermod -aG "$sudo_group" "$username"

    echo "Admin user '$username' created and added to the '$sudo_group' group."
}

# Function to configure SSH
configure_ssh() {
    echo "Configuring SSH"

    # Prompt to create or paste SSH keys
    while true; do
        read -p "Do you want to generate SSH keys (g), paste public keys (p), or generate later (l)? " ssh_choice

        if [ "$ssh_choice" = "g" ]; then
            ssh-keygen
            break
        elif [ "$ssh_choice" = "p" ]; then
            echo "Paste your public key(s) to add to authorized_keys. Type 'done' when you're finished:"
            authorized_keys=""
            while read -r key; do
                if [ "$key" = "done" ]; then
                    break
                fi
                authorized_keys="$authorized_keys$key"$'\n'
            done
            echo "$authorized_keys" > /home/"$username"/.ssh/authorized_keys
            chmod 700 /home/"$username"/.ssh
            chmod 600 /home/"$username"/.ssh/authorized_keys
            break
        elif [ "$ssh_choice" = "l" ]; then
            echo "You can generate SSH keys later. Exiting SSH configuration."
            break
        else
            echo "Invalid choice. Please choose 'g' to generate keys, 'p' to paste public keys, or 'l' to generate later."
        fi
    done

    # Disable password authentication
    read -p "Do you want to disable password authentication (y/n, default is yes)? " disable_password_auth
    disable_password_auth="${disable_password_auth:-y}"

    if [ "$disable_password_auth" = "y" ]; then
        sed -i 's/#PasswordAuthentication yes/PasswordAuthentication no/' /etc/ssh/sshd_config
    fi

    # Prompt to change SSH port
    read -p "Do you want to change the SSH port (default is 22)? " change_port
    if [ "$change_port" = "y" ]; then
        read -p "Enter the new SSH port: " ssh_port
        sed -i "s/#Port 22/Port $ssh_port/" /etc/ssh/sshd_config
    fi

    # Disable root login
    read -p "Do you want to disable root login (y/n, default is yes)? " disable_root_login
    disable_root_login="${disable_root_login:-y}"

    if [ "$disable_root_login" = "y" ]; then
        sed -i 's/#PermitRootLogin yes/PermitRootLogin no/' /etc/ssh/sshd_config
    fi

    # Restart SSH service
    service ssh restart
}

# Main script
add_admin_user
configure_ssh

echo "Setup complete."