DoubleKiller vs rdfind

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.

rdfind is a free command-line utility that finds duplicate files by comparing contents rather than names. It searches supplied directories recursively, including comparisons within or across directories, and can also accept individual files. Matching uses file size, first and last bytes, checksums, and inode or device identity. Supported checksums are MD5, SHA-1, SHA-256, SHA-512, and xxh128, with SHA-1 as the default. By default, rdfind writes a results file without changing files. Options can delete duplicates or replace them with symbolic or hard links, while a dry run previews an enabled action. Filters can ignore empty files or set minimum and maximum sizes. It runs on Linux, macOS, and Windows; Linux packages include apt and dnf examples, Mac installation can use MacPorts, and Windows users may use Cygwin. The manual warns about changing directories during a run, symlink attacks when deleting or linking, and unsupported ownership or permissions handling.