set and/or check an arduino's pinstate. for use with: https://gist.github.com/assimilat/8bb0921333054be777c6ac16318ad59d

set_pin.sh

#!/bin/bash -
#===============================================================================
#
#          FILE: set_pin.sh
#
#         USAGE: set_pin.sh
#
#   DESCRIPTION:
#
#       OPTIONS: ---
#  REQUIREMENTS: ---
#          BUGS: ---
#         NOTES: ---
#        AUTHOR: YOUR NAME (),
#  ORGANIZATION:
#       CREATED: 11/24/2021 07:39:55 AM
#      REVISION:  ---
#===============================================================================

#set -o nounset                                  # Treat unset variables as an error
if [ "$1" == "long" ];
then
  LONG_PRESS="1";
  shift
else
  LONG_PRESS="0";
fi
LONG_PRESS_DURATION="10";
MAX_PIN="8";
MOMENTARY="1 2 3 4";
DEVICE="/dev/serial/by-id/usb-1a86_USB2.0-Serial-if00-port0";
stty -F ${DEVICE} -hupcl 9600;
EXIT_SLEEP="1";
CMD_TYPE=$(echo "${1}" | sed -e "s/[0-9]//g");
TARGET_PIN=$(echo "${1}" | sed -e "s/[a-z]//g");
TARGET_STATE=$(echo "${1}" | sed -e "s/[0-9]//g");
usage() {
  (echo "Usage: ${0} <read/on/off><pin_number>";) 1>&2;
  exit;
}
momentary_check() {
for i in ${MOMENTARY};
do
  if [ "${1}" == "${i}" ];
  then
    echo "m";
    break;
  fi
done
}
if [ -z "$TARGET_PIN" ];
then
  if [ -n "$2" ];
  then
    if [ -n "$(echo "$2" | grep "[0-9]" | grep -v "[a-z]")" ];
    then
      TARGET_PIN="$2";
    fi
  else
    echo "No pin specfied!";
    usage;
  fi
fi
read_pin() {
  STATE="";
  while [ -z "${STATE}" ];
  do
    echo read${1} > ${DEVICE};
    sleep .5;
    STATE=$(head -n1 ${DEVICE} | cat -A | sed -e "s/./\n&/g" | grep "[0-9]" | tee -a /tmp/state);
  done
  if [ "$STATE" == "0" ];
  then
      echo "on";
  else
    if [ "${STATE}" == "1" ];
    then
      echo "off";
    fi
  fi;
}
write_pinstates() {
   for i in $(seq 1 ${MAX_PIN});
    do
     if [ "${i}" == "1" ];
     then
       rm /tmp/pinstate;
     fi
     PIN_STATE=$(read_pin ${i});
     if [ "${PIN_STATE}" == "off" ];
     then
        echo "${i}==off" >> /tmp/pinstate;
      else
        echo "${i}==on" >> /tmp/pinstate;
     fi
   done
}
if [ -z "$1" ];
then
  usage;
fi
if [ "$1" == "write_states" ];
then
	for i in $(seq 1 ${MAX_PIN});
	do
		echo "Pin${i}=$(read_pin ${i})";
	done
	exit
fi
if [ -z "$(echo "^${TARGET_PIN}$" | grep "[1-${MAX_PIN}]")" ];
then
  echo "${PIN} is an invalid pin";
  usage;
fi
if [ "${CMD_TYPE}" == "read" ];
then
  if [ -z "${TARGET_PIN}" ];
  then
    TARGET_PIN=$(echo $1 | sed -e "s/[a-z]//g");
  fi
  PIN_STATE="";
  while [ -z "${PIN_STATE}" ];
  do
    PIN_STATE=$(read_pin ${TARGET_PIN});
    echo "${PIN_STATE}"
  done
  exit;
fi
if [ "${CMD_TYPE}" == "write_pinstates" ];
then
  write_pinstates;
  exit;
fi
if [ "$TARGET_STATE" == "on" ];
then
  if [ "${DEBUG}" == "1" ];
  then
    echo "Setting pin ${TARGET_PIN} to on.";
  fi
  echo "off${TARGET_PIN}" > ${DEVICE};
  MOMENTARY=$(momentary_check "${TARGET_PIN}");
  while [ "$(read_pin ${TARGET_PIN})" == "off" ];
  do
    echo "on${TARGET_PIN}" > ${DEVICE};
  done
fi
if [ "${TARGET_STATE}" == "off" ];
then
  if [ "${DEBUG}" == "1" ];
  then
    echo "Setting pin ${TARGET_PIN} to off.";
  fi
  while [ "$(read_pin ${TARGET_PIN})" == "on" ];
  do
    echo "off${TARGET_PIN}" > ${DEVICE};
  done
fi
if [ "${MOMENTARY}" == "m" ];
then
  if [ "${LONG_PRESS}" == "1" ];
  then
    sleep "${LONG_PRESS_DURATION}";
  fi
#  sleep 1;
  if [ "${TARGET_STATE}" == "on" ];
  then
    if [ "DEBUG" == "1" ];
    then
      echo "Setting ${TARGET_PIN}off";
    fi
    while [ "$(read_pin ${TARGET_PIN})" == "on" ];
    do
      echo off${TARGET_PIN} > ${DEVICE};
    done
  fi
fi
if [ "$EXIT_SLEEP" -gt "0" ];
then
  sleep ${EXIT_SLEEP};
fi