Recursively compare files

cmprec.sh

#! /bin/bash

if [[ $# != 2 ]]; then
	echo "usage: cmprec <source1> <source2>"
	exit 1
fi

SOURCE1=$1
SOURCE2=$2

echo "Preparing filenames list..." 1>&2
filenames="$((
	cd "$SOURCE1"; find -type f; cd - > /dev/null
	cd "$SOURCE2"; find -type f; cd - > /dev/null
) | sort | uniq)"
echo "List ready, starting to compare files!" 1>&2

total=$(echo "$filenames" | wc -l)
i=0
echo "$filenames" | while IFS="\n" read -r filename;
do
	filename=${filename:2}

	if cmp "$SOURCE1/$filename" "$SOURCE2/$filename" --quiet; then
		echo "OK $filename"
	else
		echo "DIFF $filename"
	fi

	i=$((i+1))
	percent=$(echo "scale=2; $i * 100 / $total" | bc -l)
	echo -ne "$i/$total files ($percent%)\r" 1>&2
done