Using both the Serial Monitor and a Bluetooth module on RX/TX

UnoBluetooth.ino

void setup() {
  String debug = "";
  // Begin the serial monitor
  Serial.begin(115200);

  /*
    I use delays to ensure certain things
    have had time to settle and for
    debugging - some are probably extraneous
   */
  delay(1000);

  // Send commands to the Bluetooth module
  Serial.print("$$$");
  delay(100);
  Serial.print("x\r");
  delay(300);

  // Store output to a string
  while(Serial.available()) {
    debug += (char) Serial.read();
  }

  // Send more commands to the Bluetooth module
  Serial.print("---\r");
  delay(100);

  // Store more output to the string
  while (Serial.available()) {
    debug += (char) Serial.read();
  }

  /*
    Both the Bluetooth module and serial monitor
    will recieve this - it's okay that the Bluetooth
    module gets this, as the program is now done.
   */
  Serial.print("\nsaid: \"" + debug + "\"");

}

void loop() {
  delay(1000);
  digitalWrite(13, HIGH);
  delay(1000);
  digitalWrite(13, LOW);
}