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Remove Duplicate Lines

Instantly remove duplicate lines from text online — keep first, keep last, or keep only unique lines with case, trim, sort and privacy-first processing.

Updated

What is the Remove Duplicate Lines?

Remove duplicate lines from any text, list, log, email, or code instantly — right in your browser. Paste your content and get a clean, unique list without uploading anything to a server.

Unlike basic removers that only keep the first match, this tool gives you full control: keep first occurrence, keep last, or remove all lines that appear more than once. Match exactly or ignore case, trim extra spaces before comparing, drop blank lines, and sort the result A–Z, Z–A, by length, or shuffle.

Perfect for cleaning email lists, SEO keywords, tags, CSV columns, log files, and developer configs. Everything runs locally for privacy, works with Windows, Mac and Unix line endings, and shows live stats so you know exactly how many duplicates were removed.

How it works

1. Paste your text Drop your list into the Input box. Each line is treated as one item — works with Excel, Google Sheets, Notepad, or logs.

2. Choose your deduplication mode

  • Keep first: preserves original order, keeps the earliest occurrence
  • Keep last: keeps the most recent occurrence (great for logs)
  • Remove all: deletes every line with a duplicate, leaving only truly unique values

3. Set matching rules

  • Case sensitive: "Admin" and "admin" are different
  • Case insensitive: treats them as the same duplicate
  • Trim whitespace: ignores leading/trailing spaces when comparing
  • Drop blanks: removes empty lines from output

4. (Optional) Sort and format Choose Preserve order, A–Z, Z–A, Shortest first, Longest first, or Shuffle. Toggle "Output trimmed" to clean spacing in the result.

5. Copy or download Your cleaned list appears instantly. Use Copy or Download.txt. All processing happens in your browser — your data never leaves your device.

Examples

Deduplicate a keyword list

Case-insensitive match with whitespace trimmed

SEO
seo
 SEO 
Content Marketing
content marketing
SEO
Content Marketing

Keep only truly unique lines

Remove all lines that appear more than once

apple
banana
apple
cherry
banana
date
cherry
date

Clean log file preserving order

Keep last occurrence and drop blank lines

ERROR 404

ERROR 500
ERROR 404
INFO start
ERROR 500
ERROR 404
INFO start

Frequently asked questions

How do I remove duplicate lines from text?

Paste your text into the input area, choose a mode (Keep first is default), and the tool instantly removes duplicates. Results update live as you type — no upload required.

Does the tool keep the first or last occurrence?

You choose. Keep first preserves the earliest line and drops later copies. Keep last keeps the most recent copy, ideal for logs or updated lists.

What is the difference between case-sensitive and case-insensitive?

Case-sensitive treats "Apple" and "apple" as different lines, so both stay. Case-insensitive treats them as duplicates and keeps only one based on your mode. Use case-insensitive for email lists and usernames.

What does "Trim whitespace" do?

When enabled, leading and trailing spaces are ignored during comparison, so " hello " equals "hello". The original spacing is preserved unless you also enable "Output trimmed".

Can I remove all lines that appear more than once?

Yes. Select Remove all mode. Instead of keeping one copy, it deletes every line with a duplicate, leaving only values that occur exactly once.

What happens to blank lines?

If "Drop blanks" is on, empty lines are removed. If off, blank lines are treated like any other line — multiple blanks collapse to one in Keep first/Keep last modes.

Can I sort the unique lines?

Yes. After deduplication you can sort A–Z, Z–A, by length, shuffle randomly, or preserve original order. Sorting happens after duplicates are removed.

Is my data private and safe?

Yes. Everything runs locally in your browser using JavaScript. Your text is never uploaded, stored, or sent to a server, making it safe for sensitive lists.

Does it work with large files and different line endings?

Yes. The tool handles Windows (\r\n), Mac (\r), and Unix (\n) line breaks automatically and processes tens of thousands of lines instantly because there is no server round-trip.

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