Extract protocol buffer messages from binary data

protomower.sh

#!/bin/bash
#
# Try to decode hidden protocol buffers message from binary

size=$(wc -c < $1)

for ((i=1; i<=$size; i++))
do
    # Skip $i bytes and decode
    dd if=$1 bs=1 skip=$i | protoc --decode_raw
    if [[ $? == 0 ]]
    then
        printf "\n"
        read -p "Removed $i bytes, continue? [Yy] " -n 1 -r
        printf "\n\n"
        if [[ ! $REPLY =~ ^[Yy]$ ]]
        then
            exit 0
        fi
    fi
done