README.md

Step 1.

Download parrott.sh and put it somewhere on your computer. eg Desktop.

Step 2.

In terminal, run:

sh parrott.sh folderA folderB

It should output all the files in folderA that are missing from folderB.

You should be able to run it on whole volumes (aka disks)

sh parrott.sh /Volumes/USB1 /Volumes/USB2

parrott.sh

#!/bin/bash

set -eo pipefail

IFS=$'\n'

SRC=$1
DEST=$2

for SRC_FILE in $(find $SRC -type f -name \*.* -print)
do
	FOUND=0
	for MATCHING_FILE in $(find "$DEST" -type f -name "$(basename "$SRC_FILE")" -print)
	do
		cmp --silent "$SRC_FILE" "$MATCHING_FILE" && FOUND=1 && break
	done

	# if FOUND=0 then echo
	if [ "$FOUND" -eq "0" ]; then
	   echo "$SRC_FILE";
	fi
done