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Duplicate Line Finder

Find, remove or isolate repeated lines in a list.

1

Input

2

Settings

3

Run

4

Results

Results will appear here once you run the tool.

About Duplicate Line Finder

Find, remove or isolate repeated lines in a list. Paste or type your text into Duplicate Line Finder, adjust the settings, and the result appears below.

Your files stay on your device. ZyncTools has no upload step: the file is read in your browser, processed there, and handed straight back to you. There is no account, no watermark and no size cap beyond what your own device can hold.

Settings. Duplicate Line Finder gives you control over action, case sensitive, ignore leading/trailing spaces and ignore empty lines.

Also known as: duplicate, unique, dedupe, lines.

How to use Duplicate Line Finder

  1. Add your input. Paste or type your text into the input box. You can also load a text file from your device.
  2. Choose your settings. Adjust action, case sensitive, ignore leading/trailing spaces and the other 1 settings to suit what you need.
  3. Run the tool. The result updates as you type. Press Run to refresh it at any point.
  4. Save the result. Copy the output, or press Download to save it. Nothing is kept once you close the tab.

Frequently asked questions

Are my files uploaded when I use Duplicate Line Finder?

No. Duplicate Line Finder runs entirely inside your browser. Your text is read locally, processed on your own device, and handed straight back to you. You can confirm this yourself: open your browser's developer tools, watch the Network tab, and run the tool — no request carries your data anywhere.

Is Duplicate Line Finder free?

Yes, completely. No account, no sign-up, no watermark on your output, and no cap on how many times you can use it. The project is open source under the AGPL licence.

Does Duplicate Line Finder work offline?

Mostly. The site caches itself after your first visit, so it keeps working without a connection. Tools that need a specialised library — PDF editing, OCR, QR codes, MP3 encoding — need a connection the first time you run them, then that library is cached too.

Related text tools

Word Counter Count words, characters, sentences and estimated reading time. Case Converter Switch text between upper, lower, title, camel, snake, kebab and more. Text Reverser Reverse text by character, word or line order. URL Slug Generator Turn titles into clean, URL-safe slugs. Find & Replace Search and replace across text, with optional regular expressions. Line Sorter Sort lines alphabetically, numerically, by length or at random.