Simple compile/flash script for AVR

flash.sh

#!/bin/bash -e

#    Author: Jakub Gonet, 2018
#
#    This program is used to compile all *.c/*.cpp files
#    present in passed directory to .hex file. Also, generated
#    .hex file can be automatically flashed into uC using avrdude.

OPTIND=1 #POSIX var, resets when getopts was used in shell
#---> variables <---#
mcu="atmega8"
avrDudeMcu="m8"
optimalizationFlag="-Os"

#---> functions <---#

#$1 - input
#$2 - output
#$3 - flags
function compile {
  local input=$1
  local output=$2
  local flags=$3
  avr-gcc -mmcu=$mcu $optimalizationFlag $flags $input -o $output
}

#$1 - name of .elf file
#$2 - name of output .hex file
function elfFileToHex {
  local input=$1
  local output=$2
  avr-objcopy -O ihex -j .text -j .data $input $output
  rm $input
}

#$1 - .hex file to be flashed
function flash {
  local hexFile=$1
  avrdude -c usbasp -p $avrDudeMcu -U flash:w:$hexFile
}

#---> entry point <---#

input=""
output=""
flash=1
flags=""

while getopts "h?i:o:f:n" opt; do
  case "$opt" in
     h)  echo "Flags:"
         echo "-h - help"
         echo "-i - a path to project root directory"
         echo "-o - name of a output file (.hex)"
         echo "-f - additional flags for avr-gcc"
         echo "-n - prevents .hex file from flashing"
	 exit 0
        ;;
     \?)echo "Bad argument. Maybe try -h ?" >&2
         exit 1
         ;;
     i)  input=$OPTARG
         ;;
     n)  flash=0
         ;;
     f)  flags=$OPTARG
         ;;
     o)  output=$OPTARG
         ;;
     :) echo "Option -$OPTARG requires an argument." >&2
        exit 1
         ;;
  esac
done

if [[ -z $input || -z $output ]]
then
  echo "-i and -o flag are absent"
  exit 1
fi

processedFiles=$(find -regextype posix-extended -regex '.*\.(c|cpp)')

compile "$processedFiles" "${output%%.*}.elf" "$flags"
elfFileToHex "${output%%.*}.elf" "${output%%.*}.hex"

if ((flash))
then
  flash "${output%%.*}.hex"
fi