rpi_print_server_setup.bash

#!/usr/bin/env bash
# Automated application of WiFi Print Server: From a Raspberry Pi Zero W to Windows 10/11 By brighterfusion from instructables
# This helper script was written by Brian Khuu on 2023 for https://www.instructables.com/WiFi-Print-Server-From-a-Raspberry-Pi-Zero-W-to-Wi/

# To run this shell script on gist (ref: https://gist.github.com/numericOverflow/ac84ffb2344409429fc3dd41aea2855f)
# Run this script via curl:
# bash <(curl -sL https://gist.github.com/numericOverflow/ac84ffb2344409429fc3dd41aea2855f/raw/rpi_print_server_setup.bash)
# Run this script via wget:
# bash <(wget -o /dev/null -nv -O - https://gist.github.com/numericOverflow/ac84ffb2344409429fc3dd41aea2855f/raw/rpi_print_server_setup.bash)

echo "Automated application of WiFi Print Server: From a Raspberry Pi Zero W to Windows 10/11 By brighterfusion from instructables"
echo "Assuming you have already done Step 1 of prepping and loading in the MicroSD card and loggin in here via ssh"

### Install Packages ###
echo "### Step 2: Initialize the RPi and Install Packages ###"

# Sync RPI package lists (Removed 'upgrade -y' to prevent script hangs/reboots)
sudo apt update -y

# Install CUPS and SAMBA. 
# DEBIAN_FRONTEND=noninteractive prevents apt from hanging on config prompts
sudo DEBIAN_FRONTEND=noninteractive apt install -y cups samba

# Install the CUPS print server and SAMBA file sharing packages. This will take a several additional minutes.
# Always add the current user to lpadmin so they have web access
sudo usermod -a -G lpadmin $USER

### Config CUPS ###
echo "### Step 3: Config CUPS ###"

#########################################

# Ask if the user wants to set up a dedicated, shell-less admin user
while true; do
    read -p "Do you want to setup a dedicated CUPS web-admin user? (y/n): " SETUP_ADMIN < /dev/tty
    case $SETUP_ADMIN in
        [Yy]* ) 
            # Prompt for username (default: cups_admin_user)
            read -p "Enter CUPS admin username [cups_admin_user]: " ADMIN_USER < /dev/tty
            ADMIN_USER=${ADMIN_USER:-cups_admin_user}

            # Check if user already exists
            if id "$ADMIN_USER" &>/dev/null; then
                echo "User '$ADMIN_USER' already exists. Skipping user creation."
            else
                # Allow Web Authentication (Bypass PAM shell check) so we can add user
                if ! grep -q "/usr/sbin/nologin" /etc/shells; then
                    echo "/usr/sbin/nologin" | sudo tee -a /etc/shells > /dev/null
                fi

                # Add user with no login shell
                sudo useradd -m -s /usr/sbin/nologin "$ADMIN_USER"
                echo "Created user '$ADMIN_USER'."

                # Prompt for password
                while true; do
                    read -s -p "Enter password for '$ADMIN_USER': " ADMIN_PASS < /dev/tty
                    echo "" < /dev/tty # Move to a new line after hidden input
                    read -s -p "Confirm password for '$ADMIN_USER': " ADMIN_PASS_CONFIRM < /dev/tty
                    echo "" < /dev/tty
                    
                    if [ "$ADMIN_PASS" = "$ADMIN_PASS_CONFIRM" ]; then
                        if [ -z "$ADMIN_PASS" ]; then
                            echo "Error: Password cannot be empty."
                            continue
                        fi
                        break
                    else
                        echo "Error: Passwords do not match. Please try again."
                    fi
                done

                # Set the password non-interactively
                echo "$ADMIN_USER:$ADMIN_PASS" | sudo chpasswd
                echo "Password set for '$ADMIN_USER'."
            fi

            # Ensure the user is in the administrative group for the printers 
            # (This runs regardless of whether the user was just created or already existed)
            sudo usermod -aG lpadmin "$ADMIN_USER"
            echo "Ensured '$ADMIN_USER' is in the 'lpadmin' group."
            break;;
        [Nn]* ) 
            echo "Skipping dedicated admin user setup. Current user ('$USER') will be used for CUPS admin."
            break;;
        * ) echo "Please answer y or n.";;
    esac
done

#########################################

# Tell cups to accept print jobs from other computers on the network
# WARNING: --remote-any opens the port to all networks. Use with caution on public WiFi.
sudo cupsctl --remote-any

# Enable web-based admin pages
sudo cupsctl WebInterface=yes

# Restart CUPS
sudo systemctl restart cups

### Configure SAMBA ###
echo "### Step 4: Config SAMBA ###"

# Instead of using fragile 'patch' line-numbers, use awk to find the exact sections 
# and change the variables safely, regardless of the Samba version.

sudo awk '
    /^\[printers\]/ { section="printers" }
    /^\[print\$\]/ { section="printers_share" }
    /^\[/ && !/^\[printers\]/ && !/^\[print\$\]/ { section="" }
    
    {
        if (section == "printers" && /guest ok = no/) {
            sub(/guest ok = no/, "guest ok = yes")
        }
        if (section == "printers_share" && /read only = yes/) {
            sub(/read only = yes/, "read only = no")
        }
        print
    }
' /etc/samba/smb.conf > /tmp/smb.conf.tmp && sudo mv /tmp/smb.conf.tmp /etc/samba/smb.conf

# Restart Samba service.
sudo systemctl restart smbd

echo "Automated Portion Done..."
echo "Now you can proceed to Step 5: On CUPS Config Web Site..."