Add bin/install-printer.sh for Rongta RP326 CUPS setup

Installs CUPS and required print filter packages, configures CUPS to
listen on the local subnet (not just localhost), and registers a named
printer queue using the Rongta Printer80.ppd driver.

Requires PRINTER_HOST (device network address) and PRINTER_NAME (CUPS
queue name) to be set; validates both before proceeding.  All CUPS
config changes are idempotent.

Made-with: Cursor

Author: romkey

bin/install-printer.sh

@@ -0,0 +1,113 @@
+#!/bin/sh
+#
+# install-printer.sh
+# Install CUPS and configure the s2-receipt printer (Rongta RP326).
+#
+# Prerequisites:
+#   PRINTER_HOST  - network hostname or IP address of the Rongta RP326 device
+#   PRINTER_NAME  - CUPS queue name for the printer (e.g. s2-receipt)
+#   Rongta driver - must be installed before running this script;
+#                   it provides /usr/share/ppd/rongta/Printer80.ppd
+
+PPD=/usr/share/ppd/rongta/Printer80.ppd
+
+# ── Check prerequisites ────────────────────────────────────────────────────────
+err=0
+
+if [ -z "$PRINTER_HOST" ]; then
+    echo "Error: PRINTER_HOST is not set." >&2
+    echo "  Set it to the hostname or IP address of the Rongta RP326 device." >&2
+    echo "  Example: PRINTER_HOST=192.168.1.100" >&2
+    err=1
+fi
+
+if [ -z "$PRINTER_NAME" ]; then
+    echo "Error: PRINTER_NAME is not set." >&2
+    echo "  Set it to the desired CUPS queue name for the printer." >&2
+    echo "  Example: PRINTER_NAME=s2-receipt" >&2
+    err=1
+fi
+
+if [ "$err" -ne 0 ]; then
+    echo "" >&2
+    echo "The Rongta RP326 printer driver must also be installed first." >&2
+    echo "It should provide: $PPD" >&2
+    exit 1
+fi
+
+# ── Install packages ───────────────────────────────────────────────────────────
+echo "==> Installing CUPS and print filter packages..."
+sudo apt-get install -y \
+    cups \
+    libcupsimage2 \
+    cups-filters \
+    cups-pdf \
+    ghostscript \
+    poppler-utils \
+    qpdf \
+    imagemagick
+
+# ── Check PPD ─────────────────────────────────────────────────────────────────
+if [ ! -f "$PPD" ]; then
+    echo "Error: Rongta PPD not found at $PPD" >&2
+    echo "Install the Rongta RP326 driver package and re-run this script." >&2
+    exit 1
+fi
+
+# ── Configure CUPS for local network access ───────────────────────────────────
+echo "==> Configuring CUPS..."
+
+CUPSD_CONF=/etc/cups/cupsd.conf
+
+# Ensure CUPS listens on all interfaces, not just localhost.
+# Explicit grep check makes this safely re-runnable.
+if sudo grep -q '^Listen localhost:631$' "$CUPSD_CONF"; then
+    sudo sed -i 's/^Listen localhost:631$/Port 631/' "$CUPSD_CONF"
+    echo "  Changed Listen localhost:631 -> Port 631"
+else
+    echo "  Port 631 already set, skipping"
+fi
+
+# Add Allow @LOCAL after every "Order allow,deny" line so subnet clients
+# can browse and print.  The grep anchors to actual directives (leading
+# whitespace, not a comment #) so a commented-out example line won't
+# falsely satisfy the check.
+if ! sudo grep -q '^[[:space:]]*Allow @LOCAL' "$CUPSD_CONF"; then
+    sudo sed -i '/Order allow,deny/a\  Allow @LOCAL' "$CUPSD_CONF"
+    echo "  Added Allow @LOCAL to Location blocks"
+else
+    echo "  Allow @LOCAL already present, skipping"
+fi
+
+# Advertise shared printers via DNS-SD so clients can discover them.
+# cupsctl is idempotent.
+sudo cupsctl --share-printers
+
+sudo systemctl enable --now cups
+sudo systemctl restart cups
+echo "CUPS configured (listening on subnet, printer sharing enabled)."
+
+# ── Install the printer queue ─────────────────────────────────────────────────
+echo "==> Installing printer queue '$PRINTER_NAME' -> $PRINTER_HOST ..."
+
+# Remove any existing queue with the same name so this is idempotent.
+sudo lpadmin -x "$PRINTER_NAME" 2>/dev/null || true
+
+# Add the printer.  Port 9100 is the standard raw/JetDirect socket used
+# by Rongta and most thermal network printers.
+sudo lpadmin \
+    -p "$PRINTER_NAME" \
+    -E \
+    -v "socket://${PRINTER_HOST}:9100" \
+    -P "$PPD" \
+    -D "Rongta RP326 Receipt Printer" \
+    -L "s2"
+
+# Make it the system default.
+sudo lpoptions -d "$PRINTER_NAME"
+
+echo "Printer '$PRINTER_NAME' installed and set as default."
+echo ""
+echo "Test with:  echo 'Test print' | lpr -P $PRINTER_NAME"
+echo "Status:     lpstat -p $PRINTER_NAME"
+echo "CUPS UI:    http://$(hostname -I | awk '{print $1}'):631"