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Remove Duplicate Lines

Instantly remove duplicate lines from any text. Choose case-sensitive matching, trim whitespace, ignore empty lines, or sort the result — all in your browser.

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Unique Lines
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Duplicates Removed
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Output Characters
⚙️ Deduplication Options
📝 Input Text 0 lines
✅ Deduplicated Output 0 lines

What Does "Remove Duplicate Lines" Do?

This tool scans your text line by line and keeps only the first occurrence of each unique line. Anything that repeats is removed. It's essential for cleaning up lists, log files, email lists, product SKUs, URLs, and any dataset where the same entry appears more than once.

How to Use It

  • Paste your text into the input box — one item per line.
  • Choose your options — case sensitivity, trimming, sorting, and more.
  • Click "Remove Duplicates" and the cleaned result appears instantly.
  • Copy or download the result as a `.txt` file.

Options Explained

  • Case-sensitive: When ON, Apple and apple are treated as different lines. When OFF, they're considered the same and only the first occurrence is kept.
  • Trim whitespace: Removes leading and trailing spaces from each line before comparing. So " Banana" and "Banana" count as duplicates.
  • Remove empty lines: Deletes blank lines from the output, useful when your input has extra spacing.
  • Sort alphabetically: Sorts the deduplicated output A → Z (case-insensitive by default).
  • Numeric sort: If your lines start with numbers, sorts them numerically instead of alphabetically. So 10 comes after 9, not after 1.
  • Reverse order: Flips the final list upside down.

Common Use Cases

  • Email lists — remove duplicate addresses before importing into a CRM.
  • Product SKUs — clean inventory spreadsheets.
  • URL lists — deduplicate sitemap or backlink lists.
  • Log files — reduce noise in server or app logs.
  • Keyword lists — remove repeated terms before SEO analysis.
  • Name lists — clean up guest lists, mailing lists, or attendance sheets.
  • Code — quickly identify unique lines in a config or import block.

How It Works Under the Hood

The tool splits your input on newline characters (\n), optionally trims each line, then uses a JavaScript Set to track which lines have already been seen. Lines are added to the output only on their first appearance. If sorting is enabled, the deduplicated list is then sorted using either alphabetic comparison or natural numeric sorting.

Privacy Note

Everything runs in your browser. Your text is never uploaded to a server, never stored, and never shared. Close the tab and it's gone.