Frequently Asked Questions

RCompare is a fast, free, and open-source file and directory comparison toolkit written in Rust. It includes a CLI, a Slint desktop GUI, a PySide6 desktop GUI, and a C FFI for patch/diff integration.

Yes! RCompare is completely free and open-source under the MIT and Apache-2.0 licenses. You can use it for personal or commercial purposes without any cost. There are no premium features, subscriptions, or hidden fees.

RCompare runs on:

• Windows - Windows 10 and 11 (64-bit)
• macOS - macOS 11 (Big Sur) and later, both Intel and Apple Silicon
• Linux - Ubuntu 20.04+, Fedora 35+, Arch Linux, and most modern distributions

RCompare uses BLAKE3 for hashing, which achieves speeds of approximately 3GB/s on modern CPUs - significantly faster than MD5 or SHA-256. Combined with parallel directory traversal and a persistent hash cache, RCompare can compare millions of files efficiently while using minimal memory (~100-200 bytes per file).

No. RCompare operates 100% offline and never collects any data, telemetry, or usage statistics. Your files and comparison results never leave your computer. This is a core principle of the project.

RCompare supports:

• Directories - Full recursive comparison
• Text files - With whitespace, case, and regex normalization options
• Images - Pixel comparison with optional EXIF metadata checks
• Binary files - Byte-level and hex-oriented comparison
• Archives - ZIP, TAR, TAR.GZ, TGZ, 7Z, RAR (read-only)
• Structured data - CSV, Excel, JSON, YAML, and Parquet formats

Yes! RCompare supports cloud and remote storage:

• S3/S3-Compatible - AWS S3, MinIO, DigitalOcean Spaces, Wasabi
• WebDAV - Nextcloud, ownCloud, Apache mod_dav
• SFTP - Any SSH server with SFTP support

RCompare maintains a persistent cache of file hashes to avoid re-computing them for unchanged files. The cache stores the BLAKE3 hash along with the file's size and modification timestamp. On subsequent comparisons, if a file hasn't changed, the cached hash is used instead of reading the entire file again. This dramatically speeds up repeated comparisons.

Cache locations:

• Linux: ~/.cache/rcompare/
• Windows: %LOCALAPPDATA%\rcompare\cache\
• macOS: ~/Library/Caches/rcompare/

In CLI output:

• == - Files are identical
• != - Files are different
• << - File exists only on the left side
• >> - File exists only on the right side
• ?? - Same size but not verified (use --verify-hashes)

Yes. The CLI is designed for automation and supports multiple workflow commands:

You can also use --no-color for cleaner logs and copy/read commands for file-level automation.

Use the -i or --ignore flag with glob patterns:

RCompare also automatically respects .gitignore files in the directories being compared.

RCompare supports text-oriented diff workflows with configurable matching behavior:

• Whitespace handling modes (all, leading, trailing, changes)
• Case-insensitive comparison mode
• Regex-based normalization rules
• Line-level reports in CLI/JSON outputs

These options are available in both full scans and focused diff-file command workflows.

Contributions are welcome! You can:

• Report bugs or request features on GitHub Issues
• Submit pull requests with improvements
• Improve documentation
• Help with translations
• Spread the word about RCompare

Check out the GitHub repository for contribution guidelines.

RCompare currently has:

• rcompare_gui (Slint) - Native Rust desktop frontend focused on core compare workflows
• rcompare_pyside (PySide6) - Advanced desktop frontend with multi-session tabs, profiles, and richer session management

Yes. The rcompare_ffi crate provides a libkomparediff2-compatible C API for parsing and manipulating patch/diff data, including apply/unapply and serialization workflows.