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About Duplicate Lines Remover Online
This tool removes duplicate lines from a list. Paste your input, choose whether to keep the first or last occurrence, and the tool returns deduplicated output. Optionally trim whitespace from each line, ignore case, or sort the result.
Useful when cleaning up email lists before sending, deduplicating IPs or domains in security logs, removing repeated lines from log files, processing exported CSV columns, or merging text from multiple sources.
The tool also reports how many duplicates were removed and shows you the original count alongside the cleaned count, which makes verification trivial.
How to use this tool
How to remove duplicate lines
Paste your list
Put the lines into the Text field. The tool splits on \n and \r\n, so log dumps and spreadsheet columns both work.
Mind exact-match rules
Lines are compared verbatim — "alice" and " alice" stay distinct, and so do "alice" and "Alice". Trim or lowercase first if you want fuzzy dedupe.
Run the dedupe
Press Run. The first occurrence of each line is kept, later duplicates are dropped, and the original order is preserved.
Copy the cleaned list
Output appears below. Copy it back into your sheet, ticket, or config file.