ddiff

A small utility that checks if two folders are the same.

How it works

ddiff is a simple CLI binary written in Rust that computes the hash of every file inside two different folders and look for files inside the first folder but not inside the second folder, and viceversa, or files with matching path but different content (hash).

Why?

Very often I have to check if two folders are the same or not (i.e. copying very important files over the network) and since I’m really paranoid about data integrity, I usually compute the hash of every file in the two folders and compare them.

This works but it’s not easy, it’s not fast and certainly it’s not elegant.

I know there is a solution to this problem involving rsync but IMHO it’s as bad as the “naive”/manual one.

So I decided to build a tool to solve this problem.

Installation

1. Install from Cargo (requires Rust toolchain):

   cargo install ddiff

2. Download binary from releases page and add it to you $PATH. Available for linux and macOS on "x86"

Usage

``` ddiff 0.1.0

USAGE: ddiff

FLAGS: -h, --help Prints help information -V, --version Prints version information

ARGS:
```

Example output

```

Files with same path but with different hash

path         hash A                                                            hash B
file_random  9b53eed45673c3e91f365f66c9138117bc595888bcdc63f907fafdb28cb72bca  49d138ac765678706c3cc84721af69d66dcb91dfaa71b46e469d296e0788b133

Files in testA/ but not in testB

path      hash testA/  hash testB
unique_a  16b3a442c222b958453e73cb818a51a060bed10b9bf6649f2bbb43a9e57bff78

Files in testB but not in testA/

path      hash testB  hash testA/
unique_b  16b3a442c222b958453e73cb818a51a060bed10b9bf6649f2bbb43a9e57bff78

ddiff checked 6 files, about 28 B, in 17.220658ms ```

Hashing

This tool uses the BLAKE3 hashing algorithm.

I know... a non-cryptographic hash would be better, but I really like the properties of cryptography hashes and there is a really cool utility called b3sum to verify the hashes. It’s also fast enough to not be a bottleneck on almost any machine, especially since ddiff it’s multithreaded (thanks Rayon)

Roadmap

• [ ] Add unit tests and more integrations tests
• [ ] Add benchmarks
• [ ] Build ARM binaries IMPORTANT
• [ ] Improve documentation and publish it
• [ ] Add a simple installation script
• [ ] Publish on Homebrew and other package managers

Contributing

Probably no one will ever read this, but in the rare case that you end up here and you want to add some features, improve my code, suggest a new functionality, or more probably to fill up a issue to fix a bug, etc., in any case you are welcome to make PRs, fill issues, or send me a mail.

I'm also very interested in real-world test cases and usage scenarios. Let me know if this small utility was useful to you or if you have any idea on how to improve it.

Contributing

Git hooks

This repository has git pre-commit hook to enforce good formatting, code linting, and testing on developer side (thanks cargo-husky), the same rules will be applied on GitHub Actions.

Conventional commits

This repo follow Conventional Commits even if is not enforced by a commit message hook.

Continuous Integration/Delivery

This project use GitHub Actions for CI and building releases.

Thanks to the awesome action-rs project.

License

This project is licensed under the MIT license.