fclones vs jdupes

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.

jdupes is a free utility for finding and handling exact duplicate files on Linux, macOS, and Windows. It identifies files that are fully identical rather than matching images, sounds, or other formats by similarity. Matching can use file size, hashes, and byte-for-byte comparison, with optional partial-hash matching. The project says it checks matching data after hashing to reduce the chance of false matches from hash collisions. Found duplicates can be reviewed before deletion, deleted without prompting, linked, summarized, or handled through copy-on-write deduplication. On Linux and Unix, the instructions use command-line directory paths; the project also provides a native Windows port, including support for Unicode. Docker use is documented, and standard output can feed shell scripts. A database can retain scan metadata for repeat runs, though the project labels that feature as under development and notes quirks. The README warns that quick matching skips byte-for-byte checks and can classify non-duplicates as duplicates. It also warns that disabling file-change checks creates a security vulnerability, especially when linking or deleting. jdupes is distributed under the MIT License.