Fair enough. I hadn't noticed. And in a certain sense it does use them. Whatever, since your proposed solution

do { print if delete $unique{$_} } for @lines;

[download]

although perfectly working is not that intuitive and I seem to remember that deleting elements has an effective execution load, I'd still stick with a %saw-like solution. But I admit that all in all yours is an interesting and smart use of delete.

In reply to Re^4: Deleting duplicate lines from file by blazar
in thread Deleting duplicate lines from file by Win

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