DupMerge (often referred to as Dupemerge) is a utility designed to reclaim disk space by identifying identical files and merging them using hardlinks or symbolic links.
Instead of deleting duplicates and potentially breaking software that expects a file in a specific location, it replaces duplicates with links that point to a single physical copy on the disk. Key Features
Space Saving via Hardlinks: It uses the NTFS file system functionality to link identical files together. Since hardlinks don’t take up additional space, you keep the files in their original locations while only storing one copy on the drive.
Content-Based Identification: It finds duplicates by comparing file size and content (using cryptological hashsums like MD5) rather than just file names or dates.
Flexible Linking Options: Modern versions (like the Hawkynt/DupMerge GitHub project) allow for both hard links and symbolic links, as well as the ability to remove links or replace them with copies.
Performance Optimization: It often features multithreading support and incremental hashing (checking the first few kilobytes first) to speed up scans on large hard drives.
Command Line Focus: Most versions are command-line utilities intended for power users or for inclusion in batch/CMD scripts. Available Versions Primary Developer / Source Key Characteristics Original Dupemerge Hermann Schinagl
A classic Windows command-line utility optimized for NTFS hardlinks. DupMerge (C#) Hawkynt (GitHub)
A .NET-based version with multithreading and symbolic link support. dupmerge2 SourceForge
A continuation of the older program with added sparse and deletion modes.
Safety Tip: When using tools that create hardlinks, be aware that modifying one “copy” of a hardlinked file will change the content for all linked paths, as they all point to the same physical data on the disk. dupemerge – Hermann.Schinagl
Leave a Reply