Bonus:

Explanation: asking for a program to effectively remove duplicates gives 14 programs that do essentially the same (therefore, making them duplicates).

Relevant XKCD:

https://xkcd.com/927/

  • I always found the actual challenge to decide what to get rid of once the duplicates where found.

    Some tools I tried would also ask file-by-file, which I found a bit useless for thousand of files. Yet, I cannot even express a set of rules to decide this in general, so I’m not blaming the tools.

    In particular, with picture collections I also came to the conclusion that some redundancy is probably ok rather than accidentially deleting data that I duplicated on purpose and simply forgot why.