DoubleKiller vs fclones

DoubleKiller is a Windows utility that finds duplicate files in directories, on complete drives or on computers in Network Neighborhood. It can compare files using any combination of name, size, modification date and content. Scans can exclude files by name, type, attributes or size, and the results list lets users choose files to delete or move to another directory. Results can also be exported to a text file. The program is a standalone executable that can be extracted and run without installation; its maker says it does not change the system without prior permission. The free version is for private use and allows unlimited folder and file counts, but individual files are limited to 2 GB and commercial use is not permitted. DoubleKiller Pro adds a multilingual interface, advanced comparison options, saved and reloadable result lists, and command-line automation. The download page lists version 1.6.2.82 dated 2007-07-07, and the maker says development is paused. The listed paid starting price is $19.95 one-time.

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.