Arduino (uC) over serial api

starting to write a simple arduino over serial api... ( although my C is total rubbish )...

currently using it for LCD-hd44780 ( i.e. ...)

<1, 1, this is line 1>      #lcd
<1, 2, this is line 2>      #lcd
<2, GPIOn, OFF>             #gpio?
<2, GPIOn, ON>              #gpio?
<3, AnaloguePINn, READ>     #analogue?
<3, AnaloguePINn, 255>      #analogue?

if anyone has done this or is interested would be good to pool needs/code/ideas... etc...

the idea is to wrap serial logic and then provide further access via shell/mqqt wrapper scripts... i.e.;

arduino.sh lcdline1 "message"
arduino.sh get gpio 9
arduino.sh set gpio 9 ON
http://127.0.0.1/arduino?gpio=9&set=ON