Set DISPLAY directly. No need to parse arg

install_as_service.sh

@@ -1,14 +1,7 @@
 #!/bin/bash
 chmod +x run.sh
 # If first arg is of form :n it will set DISPLAY to :n. Default is :0
-dsp_prefix=:
-dsp=:0
-# if [[ -n "${1+x}" ]]; then
-    if [[ $1 == $dsp_prefix* ]]; then
-        dsp="$1"
-        shift
-    fi
-# fi
+dsp=$DISPLAY
 args="$*"
 rm -f fwledmonitor.service || true
 sed -i "s#led_system_monitor.py.*\$#led_system_monitor.py ${args}#" run.sh