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Duplicate line remover
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About this tool
Remove duplicate lines while retaining the first or last occurrence in source order.
Common uses
- Remove duplicate lines while retaining the first or last occurrence in source order.
- Choose trimming, case-insensitive comparison and blank-line removal before deduplicating.
How to use it
- 1.Choose trimming, case-insensitive comparison and blank-line removal before deduplicating.
- 2.Select first or last occurrence retention and copy the remaining lines with the reported count.
Worked example
Input and result
a b a (keep last)
b a
Keeping last occurrences preserves their relative order.
Limits and notes
- Trimming changes the output text as well as comparison keys. Keeping the last occurrence preserves the relative order of those last occurrences; it does not sort the lines.
Frequently asked questions
What does this tool do?
Remove duplicate lines while retaining the first or last occurrence in source order.
What should I check before using the result?
Trimming changes the output text as well as comparison keys. Keeping the last occurrence preserves the relative order of those last occurrences; it does not sort the lines.