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Duplicate groups

DupliWalker does not hand you a list of files. It hands you groups, and a group is the unit you make decisions about.

Why grouping is the right shape

A duplicate is never a property of one file. “This file is a duplicate” is meaningless on its own — a duplicate of what? Duplication is a relationship between two or more files, and the relationship is what you need to see to decide anything.

A flat list would also hide the one fact that matters most: how many copies exist. Deleting “the duplicates” from a group of two means keeping one. Doing the same to a group of five means keeping one and removing four. Those are very different actions, and a list makes them look identical.

What a group contains

Every member of a group has the same content. They differ in the things that do not affect content:

  • where they live
  • what they are called
  • when they were last modified
  • which side they are on — Dupli or Reference

Reading a group is mostly reading that table and deciding which row is the one you would miss.

Choosing the copy to keep

If you have set up Reference folders, much of this is already decided: the Reference copy stays.

Otherwise, useful tie-breakers, roughly in order:

  1. Location. The copy in the folder where you would look for it in a year.
  2. Name. holiday-2019-portugal.jpg beats IMG_4021 (2).jpg.
  3. Surroundings. A copy that sits inside a coherent folder structure is worth more than a loose one, even if identical.
  4. Date. The least reliable of the four — copying a file can change its date without changing anything about the file.

Since the contents are identical, none of this affects what you keep — only where it is and what it is called. That is a filing decision, not a data one.

Count versus reclaimable space

Two numbers that are easy to confuse:

  • Duplicate count — how many files are involved.
  • Reclaimable space — how much you get back if you reduce each group to one copy.

They are not proportional. Ten thousand duplicated text files may free less space than three duplicated videos. If your goal is disk space, sort by size and start at the top; if your goal is tidiness, count is the better guide.

Reclaimable space always excludes one copy per group, because you are keeping one. A group of three 1 GB files represents 3 GB on disk but only 2 GB reclaimable.

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Dupli and Reference foldersIdentical folders