Here you go: cd /path/to/drive find . -type f -exec sha256sum {} + | sed -E 's/^([^ ]+) \./\1,/' >> ~/all_hashes.txt Run that for each drive, then whe

Here you go: cd /path/to/drive find . -type f -exec sha256sum {} + | sed -E 's/^([^ ]+) \./\1,/' >> ~/all_hashes.txt Run that for each drive, then when you're done run: sort ~/all_hashes.txt > ~/sorted_hashes.txt awk -F, 'NR==1{print;next} {print $0 | "sort | uniq -w64 -D"}' ~/sorted_hashes.txt > ~/non_unique_hashes.txt The output in ~/non_unique_hashes.txt will contain only the non-unique hashes that appear on more than one path.