A Bash script that switches between two displays depending on display connectivity

dispd.sh

#! /bin/bash

# dispd: Display Switcher daemon v1.0-(092015)
# by Sophie Forceno
# 
# dispd will enable and make active one of two displays depending on which is plugged in
# Currently, allows you to switch between native laptop display and external HDMI monitor
# Execute 'dispd &' to run in background
# Then, plug/unplug your external display and watch the magic happen!
#
# Distributed under an "I-don't-care-what-you-do-with-this" license

# Change these depending on system configuration
INT="LVDS1"
EXT="HDMI1"

# Main loop
while true
do
# Change these depending on system configuration
LVDS=$(cat /sys/class/drm/card0-LVDS-1/enabled)
HDMI=$(cat /sys/class/drm/card0-HDMI-A-1/status)

if [[ $HDMI = "connected" ]]; then 
# Commented out because it is unique to my system configuration
# You may not need it
      #xrandr --addmode HDMI1 1920x1080
# Change --mode or remove it depending on your configuration
      xrandr --output $INT --off --output $EXT --mode 1920x1080
 
elif [[ $HDMI = "disconnected" ]] && [[ $LVDS = "disabled" ]]; then 
# Change or remove --mode depending on your cnofiguration
  	  xrandr --output $INT --mode 1280x800 --output $EXT --off
fi
# Sleep = 1s produces the least delay possible
    sleep 1s
done