#!/bin/bash
optstring="o:"
input_files=""

while getopts ${optstring} args; do
	case $args in
		o) output_file=${OPTARG} ;;
		:) echo "Output file required." ;;
	esac
done

shift $((OPTIND-1))
echo $output_file


echo "Concatenating files..."
declare -i total_size=0
for fname in "$@"; do
	#TODO: Make sure this file exists and isn't a directory!
	current_file_size=$(stat -c%s "$fname")
	let total_size=$total_size+$current_file_size
	echo "${fname} is ${total_size}b and valid."
done

cat "$@" | pv -epts "$total_size" > "$output_file"

echo "Done!"