qmk_firmware/avrdude

#!/bin/bash
set -x
BUILD_DIR=.
TARGET=lets_split_rev2_adam.hex
MCU=atmega32u4
ls /dev/tty* > /tmp/1;
echo "Reset your Pro Micro now";
while [[ -z $USB ]]; do
  echo "."
  sleep 1;
  ls /dev/tty* > /tmp/2;
  USB=`diff /tmp/1 /tmp/2 | grep -o '/dev/tty.*'`;
done;
avrdude -p $MCU -c avr109 -P $USB -U flash:w:$BUILD_DIR/$TARGET