Duplicate_File_Delete_by_size/README.md

dedupe.py — Duplicate File Finder / Deleter

Scans a directory for duplicate files, keeps one copy of each, and reports or deletes the rest.

What it does

It groups files by size as a fast first pass, then confirms real duplicates by comparing SHA-256 content hashes. For each set of identical files it keeps one copy and reports (or deletes) the others.

By default the script runs in dry-run mode — it only tells you what it would delete. Nothing is removed unless you explicitly pass --delete.

⚠️ Important

Two files with the same size are not necessarily the same file. That's why the script hashes file contents before deleting. Only use size-only matching (--size-only) if you fully understand the risk of deleting unrelated files.

Requirements

• Python 3.6 or newer
• No third-party packages (standard library only)

Usage

python dedupe.py DIRECTORY [options]

DIRECTORY is the folder to scan.

Options

Option	Description
--delete	Actually delete the duplicate copies. Without this flag the script only prints what it would do (dry run).
--size-only	Match files on size alone and skip content hashing. Dangerous: same size does not mean same content.
--no-recursive	Only scan the top level of DIRECTORY; do not descend into subfolders.
-h, --help	Show the built-in help message.

Examples

# See what would be deleted in ~/Downloads (safe, nothing removed)
python dedupe.py ~/Downloads

# Actually delete verified duplicates
python dedupe.py ~/Downloads --delete

# Only look at the top level, not subfolders
python dedupe.py ~/Downloads --no-recursive

# Match purely on size (risky) — dry run first
python dedupe.py ~/Downloads --size-only

How it decides what to keep

Within each set of duplicates, the files are sorted alphabetically by path and the first one is kept. All others in the set are the candidates for deletion.

Output

For each duplicate set the script prints the file it keeps and each file it would delete (or has deleted). At the end it prints a summary with the number of files affected and the amount of disk space reclaimed.

Safety tips

1. Always run once without --delete and review the output first.
2. Make sure you have a backup before deleting anything important.
3. Avoid --size-only unless you're certain size alone is enough.