fclones

Summary

fclones is a free, open-source command-line utility for finding identical files and handling 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. The tool compares files using size, identifiers, prefix and suffix hashes, and full-content hashes. Results can be displayed as standard text, fdupes-compatible output, CSV or JSON, and the project describes integration with Unix utilities such as find. After locating duplicates, fclones can remove or move files, or replace them with soft or hard links. On supported file systems, it can deduplicate file data with native copy-on-write reflinks, but that capability is not supported on Windows. Users can inspect and modify duplicate lists before removal, and dry-run mode reports filesystem changes without carrying them out. Its Rust implementation parallelizes I/O and CPU-heavy stages and tunes processing for SSDs and HDDs. Optional persistent hash caching can help with repeated grouping and interrupted work. It runs on Linux, macOS and Windows under the MIT license.

Who it is for

fclones suits users comfortable with a command-line tool who want to find and manage duplicate files across directory trees or removable devices. Its output formats and Unix utility integration may also suit scripted workflows.

Compared on duplicate file finders

Free plan

Yesgithub.com

Platform coverage

cross-platformgithub.com

Scan locations

Directory trees, multiple directory roots, standard-input file lists, and mounted or removable devicesgithub.com

Match methods

File size, inode/file identifiers, prefix hash, suffix hash, and full-content hashgithub.com

File preview

Yesgithub.com

Automatic selection

Yesgithub.com

Folder exclusions

Yesgithub.com

Facts

Purpose

fclones identifies groups of identical files and removes unwanted copies.github.com · 1 Oct 2026

File operations

It can remove, move, or replace redundant files with soft or hard links.github.com · 1 Oct 2026

Deduplication

It can deduplicate file data using native copy-on-write reflinks on supported file systems.github.com · 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 · 1 Oct 2026

Output

It provides standard text, fdupes-compatible, CSV, and JSON output formats.github.com · 1 Oct 2026

Integrations

The project says it integrates with Unix utilities such as find and speaks JSON.github.com · 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 · 1 Oct 2026

Performance

The Rust implementation parallelizes I/O and CPU-heavy stages and automatically tunes processing for SSDs and HDDs.github.com · 1 Oct 2026

Caching

Optional persistent hash caching can speed up repeated grouping and resume interrupted work.github.com · 1 Oct 2026

Security

The repository is released under the MIT license.github.com · 1 Oct 2026

Platform limit

Copy-on-write file-data deduplication is not supported on Windows.github.com · 1 Oct 2026

Linux optimization

Physical file-access ordering and page-cache drop-behind optimizations are unavailable on platforms other than Linux.github.com · 1 Oct 2026

Support

The project provides GitHub Issues and Discussions for community support.github.com · 1 Oct 2026

Where it ranks on Everything Xiaomi

• Best Duplicate File Finders in 2026#3 of 38

Sources

• github.com/pkolaczk/fclones· checked 1 Oct 2026