This bash script is used to invoke API commands to a spark programmed with the "SPARK RC CAR KIT" sample code on this page: http://docs.spark.io/#/shields

spark_core_rc_car_bash_script.sh

# About
# =====
#
# Control a Spark Core remote control car with a bash script. Why not?
#
# Spark Core Firmware Assumptions
# -------------------------------
#
# * You have registered a function in your firmware that will allow you to hit it via the API,
#   something like:
#
#   `Spark.function("rccar", rcCarControl);`
#
#   See the RC Car docs here for this example: http://docs.spark.io/#/shields for more details
#
# Usage
# -------
#
# * Download this file
# * Open up a bash terminal (note this doesn't work in zsh for some reason).
# * Change the SPARK_CORE_DEVICE_ID and SPARK_CORE_ACCESS_TOKEN variables
# * Type `source spark_core_rc_car_bash_script.sh`
# * Type `rc_while`
# * Hit characters and watch API commands go (and hopefully your car spin around)!
#
#     f=forward, b=back, l=left, r=right, s=stop
#
#

# Change these!!!
export SPARK_CORE_DEVICE_ID=YOUR_DEVICE_ID_GOES_HERE
export SPARK_CORE_ACCESS_TOKEN=YOUR_ACCESS_TOKEN_GOES_HERE

# a loop that calls "rc" with a single character as input.
function rc_while() {
  while read -n 1 _c; do
    rc "$_c"
  done
}

# A function that maps a single character to a curl request.
function rc() {
  _base_command='curl https://api.spark.io/v1/devices/'"$SPARK_CORE_DEVICE_ID"'/rccar -d access_token='"$SPARK_CORE_ACCESS_TOKEN"' -d "params=rc,__CMD__"'
  case "$1" in
  f) echo "Forward march!"
    _command=$(echo "${_base_command}" | sed 's/__CMD__/FORWARD/')
     ;;
  b) echo "Come on back now"
    _command=$(echo "${_base_command}" | sed 's/__CMD__/BACK/')
     ;;
  l) echo "Hang a lu lu"
    _command=$(echo "${_base_command}" | sed 's/__CMD__/LEFT/')
     ;;
  r) echo "Hang a rubarb"
    _command=$(echo "${_base_command}" | sed 's/__CMD__/RIGHT/')
     ;;
  s) echo "Stop!"
    _command=$(echo "${_base_command}" | sed 's/__CMD__/STOP/')
     ;;
  *) echo "Don't know what to do with $1 : f=forward, b=back, l=left, r=right, s=stop"
     ;;
  esac

  echo $_command
  echo $_command | bash
}