QNAP LCD control

set_qnap_lcd.sh

#!/bin/bash

TEXT="${@:2:$#}"

function printUsage() {
  echo "Usage: $0 <off|on>"
  echo "Usage: $0 <1|2> Text Message"
  exit 0
}

function setDisplay() {
  if [ ${#2} -gt 15 ]; then
    echo "String to set can be max 16 characters!"
    exit 1
  fi

  printf "Setting line $1 on display to \"%s\"\n" "$2"
  # Text we print must be padded to exactly 16 characters to wipe old text
  printf "M\f\x`expr $1 - 1` %-16s" "$2" > /dev/ttyS1
}

if [ $# -eq 0 ]; then
  printUsage
fi

stty -F /dev/ttyS1 1200

if [ $1 = "off" ]; then
  echo "Turning display off"
  echo -e "M^\x0" > /dev/ttyS1
  exit 0
fi

if [ $1 = "on" ]; then
  echo "Turning display on"
  echo -e "M^\x1" > /dev/ttyS1
  exit 0
fi

if [ $1 = "1" ] || [ $1 = "2" ]; then
  setDisplay $1 "$TEXT"
  exit 0
fi

printUsage