ferr

File copy tool with integrity verification for DITs and backups (GUI + CLI)

Named after the Latin ferre (to carry) — built to transport your data with uncompromising integrity.

Warning

Disclaimer: Personal Project
I created this tool for my own use. I am not a professional software developer, and this project was built with the help of AI to explore certain workflows.
The code is provided "as is", without any warranties or guarantees. Use it at your own risk.

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ferr is a utility designed to help ensure file integrity during transfers. It is intended for users who need to verify that files are copied correctly, such as Digital Imaging Technicians (DITs) or those managing backups. It uses cryptographic hashing to verify data and provides optional redundancy through PAR2. It is available as a Desktop GUI application and a Command-Line Interface.

Features

ferr provides several tools to assist with data management and verification:

• Hashing: Files can be hashed during the copy process (XXH64 or SHA-256) to check for transfer errors.
• Multiple Destinations: Supports copying from one source to up to 3 destinations.
• PAR2 Support: Can generate PAR2 files to assist with possible future data repair if corruption occurs.
• Desktop GUI: A cross-platform interface built with Tauri v2 and HTML/JS.
• Transfer History: Uses a local SQLite database to keep track of completed jobs.
• File Detection: Includes basic detection for various camera file formats.
• Integrity Certificates: Supports generating and verifying portable .ferrcert files to document folder state and tracking history.
• Logging: Generates timestamped subfolders (_ferr_logs) containing job reports.

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Quick Start

Installation

1. Command-Line Interface (CLI) Only

# Requires Rust 1.75+
git clone https://github.com/freddewitt/ferr
cd ferr
cargo install --path ferr-cli

2. Desktop GUI (ferr-app)

To build the graphical application on macOS, you must compile the CLI as a sidecar:

# 1. Build the engine
cargo build --release -p ferr-cli

# 2. Copy to the Tauri binaries folder (Apple Silicon example)
cp target/release/ferr ferr-app/binaries/ferr-cli-aarch64-apple-darwin

# 3. Install Tauri v2 CLI
cargo install tauri-cli --version "^2.0.0"

# 4. Build the application
cd ferr-app
cargo tauri build
# The app bundle will be at: target/release/bundle/macos/ferr.app

Basic Usage

# Copy a folder and verify integrity (defaults to XXH64)
ferr copy /Volumes/SOURCE /Volumes/DEST

# Copy to two destinations with 5% PAR2 redundancy
ferr copy /Volumes/CARD /mnt/ssd1 --dest2 /mnt/ssd2 --par2 5

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Usage Scenarios

1. Integrity Certificates (ferr cert)

You can generate portable certificates to document the state of a folder. These are useful for verifying data integrity across different systems. For a detailed technical explanation of how they work, see ferrcert.md.

• Create: ferr cert create /MyData
• Verify: ferr cert verify /MyData/MyData.ferrcert /ReceivedData

2. Rename on Copy

Basic support for renaming files based on metadata during the copy process:

ferr copy /Volumes/A001 /RAID --camera --rename "{date}_{camera}_{clip}{ext}"

3. Watch Mode

Monitors a path for new mounts and starts a copy automatically:

ferr watch /Volumes --dest /mnt/backups --profile onset

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Project Structure

ferr is organized into several modules:

Component	Description
ferr-app	GUI front-end.
ferr-cli	CLI interface.
ferr-core	Core logic and job management.
ferr-cert	Logic for generating and verifying integrity certificates.
ferr-par2	Wrapper for PAR2 verification and repair.
ferr-hash	Hashing implementations.
ferr-session	Session management and SQLite storage.
ferr-report	Report generation (JSON and PDF).

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Documentation

For more information on commands and options, see the:

👉 ferr CLI Reference Guide

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License

Licensed under the MIT License. See LICENSE for details.