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fclones
What it is
fclones is a free, open-source command-line utility that finds groups of identical files and helps manage unwanted copies. It can scan multiple directory roots, file lists supplied through standard input, and mounted or removable devices. Search controls include recursion limits, glob and regular-expression filters, and minimum or maximum file sizes. Results can appear as standard text, fdupes-compatible output, CSV or JSON, and the project describes integration with Unix utilities such as find. Once duplicates are identified, fclones can remove or move files, or replace them with soft or hard links. On supported file systems, it can deduplicate file data using native copy-on-write reflinks; that capability is not supported on Windows. Users can inspect and modify duplicate lists before removal, while dry-run mode reports filesystem changes without carrying them out. Its Rust implementation parallelizes I/O and CPU-heavy stages and adjusts processing for SSDs and HDDs. Optional persistent hash caching can help with repeated grouping and interrupted work. The software is released under the MIT license.
For and against
For
- Scans multiple roots and removable devices
- Offers glob, regex and size filters
- Supports text, CSV and JSON output
- Dry-run reports changes without executing them
- Optional hash cache supports repeated grouping
Against
- Copy-on-write deduplication is unavailable on Windows
- Some file-access optimizations are Linux-only
The verdict
fclones combines duplicate discovery with several ways to handle or review redundant copies. Windows users should note that copy-on-write deduplication is not supported there.
Who it suits
fclones suits command-line users who need to locate duplicate files across directory trees or device-mounted storage. Its filters, output formats and review controls can also help users who want to inspect results before changing files.
Plans and prices
Open-source fclones
MIT license · command-line utility
Read 1 Oct 2026 · github.com
On the record
- Caching
- Optional persistent hash caching can speed up repeated grouping and resume interrupted work.github.com · read 1 Oct 2026
- Deduplication
- It can deduplicate file data using native copy-on-write reflinks on supported file systems.github.com · read 1 Oct 2026
- File operations
- It can remove, move, or replace redundant files with soft or hard links.github.com · read 1 Oct 2026
- Integrations
- The project says it integrates with Unix utilities such as find and speaks JSON.github.com · read 1 Oct 2026
- Linux optimization
- Physical file-access ordering and page-cache drop-behind optimizations are unavailable on platforms other than Linux.github.com · read 1 Oct 2026
- Output
- It provides standard text, fdupes-compatible, CSV, and JSON output formats.github.com · read 1 Oct 2026
- Performance
- The Rust implementation parallelizes I/O and CPU-heavy stages and automatically tunes processing for SSDs and HDDs.github.com · read 1 Oct 2026
- Platform limit
- Copy-on-write file-data deduplication is not supported on Windows.github.com · read 1 Oct 2026
- Purpose
- fclones identifies groups of identical files and removes unwanted copies.github.com · read 1 Oct 2026
- Safety controls
- Users can inspect and modify duplicate lists before removal, and the --dry-run option reports filesystem changes without executing them.github.com · read 1 Oct 2026
- Security
- The repository is released under the MIT license.github.com · read 1 Oct 2026
- Selection
- It supports multiple directory roots, standard-input file lists, recursion limits, glob and regular-expression filters, and minimum or maximum file sizes.github.com · read 1 Oct 2026
- Support
- The project provides GitHub Issues and Discussions for community support.github.com · read 1 Oct 2026
