AllDup vs fclones

AllDup has no write-up on Specifiction yet; its figures are above.

fclones is a free command-line utility for locating groups of identical files and handling redundant copies. It runs on Linux, macOS, and Windows, and can scan multiple directory roots, standard-input file lists, and mounted or removable devices. Search controls include recursion limits, glob and regular-expression filters, and minimum or maximum file sizes. It can compare files using size, inode or file identifiers, prefix and suffix hashes, and full-content hashes. Results are available as text, fdupes-compatible output, CSV, or JSON. Once duplicates are identified, fclones can remove or move them, or replace them with soft or hard links. On supported file systems, it can deduplicate file data with native copy-on-write reflinks, a capability unavailable on Windows. Users can inspect and alter duplicate lists before removal, and dry-run mode reports changes without executing them. The Rust implementation parallelizes I/O and CPU-heavy work and adjusts processing for SSDs and HDDs. Optional persistent hash caching can help repeated scans and resumed work; the project is released under the MIT license.