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Duplicate Line Remover

Remove duplicate lines from text while preserving order. Paste a list, get unique lines instantly.

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How to Use

  1. 1

    Paste your text

    Enter your list or text with duplicate lines in the input area.

  2. 2

    Click Remove Duplicates

    The output shows only unique lines, in their original order.

  3. 3

    Copy the result

    Click Copy to copy the deduplicated text to your clipboard.

What is Duplicate Line Remover?

A duplicate line remover scans a block of text line by line and keeps only the first occurrence of each unique line, removing all subsequent duplicates. The original order of lines is preserved — the first appearance of each line stays in place. Lines are compared exactly: same content (including capitalization and whitespace) means duplicate; different content means unique.

This online tool is useful for deduplicating lists, email addresses, log entries, CSV rows, URLs, IP addresses, or any line-based data where duplicates have crept in. It is faster than writing a one-liner with `sort -u` (which also reorders) or `awk '!seen[$0]++'` for one-off cleanup in the browser.

To deduplicate while sorting, use the [Line Sorter](/tools/line-sorter/) with the "Remove duplicates" option enabled. To remove blank lines too, run the [Empty Line Remover](/tools/empty-line-remover/) afterwards. For case-insensitive deduplication, convert text to lowercase first using the [Case Converter](/tools/case-converter/), then deduplicate.

FAQ

Is the comparison case-sensitive?
Yes, 'Apple' and 'apple' are treated as different lines. If you need case-insensitive deduplication, convert to lowercase first using the Case Converter, then deduplicate.
Does it preserve the original order?
Yes. The tool keeps the first occurrence of each line and removes later duplicates. The relative order of unique lines is unchanged.
How does it handle empty lines?
All empty lines after the first one are treated as duplicates and removed. If you want to remove all empty lines entirely, use the Empty Line Remover.
How is this different from sort -u or awk on the command line?
`sort -u` reorders lines alphabetically before deduplicating, which loses the original order. `awk '!seen[$0]++' file.txt` preserves order (same as this tool). For files in the terminal, `awk` is fast and scriptable. For one-off browser cleanup of lists or pasted data, this online tool is more convenient — no installation, no command syntax, and you can compare the input and output side by side.

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