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Duplicate Line Finder
Find duplicate lines in text, see occurrence counts and line numbers, and copy a cleaned list. Choose case and whitespace options.
Your results will appear here.
Three steps. That’s it.
A useful toolkit for text, data, images and calculations.
- 01
Add your input
Choose a tool, enter values or select a file.
- 02
Make it yours
Adjust the options and run the action.
- 03
Take the result
Copy the result or download its file.
What this tool does
Identify repeated values in a pasted list without losing their original order. This is useful for reference numbers, email lists, exported IDs and copied log entries. The results show which values repeat, how often they occur and their line numbers. You can export one copy of each value or only values that appeared more than once.
How to use it
Paste one value per line. Decide whether to ignore case, trim spaces or skip blank lines. Select Find duplicates and choose the export you need.
Example
apple banana apple
The example contains two apple entries. Exporting unique lines gives apple and banana.
Does it compare entire lines?
Yes. It compares complete lines rather than individual words. Case and whitespace options change which lines count as equal.
Where is my text processed?
The bundled tool code processes text in your browser. It does not send or save your input. Extensions and other site plugins may have separate behavior.
Duplicate line detector online
Identify repeated values in a pasted list without losing their original order. This is useful for reference numbers, email lists, exported IDs and copied log entries. The results show which values repeat, how often they occur and their line numbers. You can export one copy of each value or only values that appeared more than once.
How to use it
Paste one value per line. Decide whether to ignore case, trim spaces or skip blank lines. Select Find duplicates and choose the export you need.
Options and example settings
Worked examples
Check repeated IDs, reference numbers or copied log entries before cleaning a list. Complete lines are compared, not individual words or CSV columns.
Repeated IDs with leading zeros
Settings: Trim spaces enabled; ignore case enabled; skip blank lines enabled; unique-line export
Input:
00123 00456 00123
00123 appears twice at lines 1 and 3. The unique export keeps first-occurrence order.
Output:
00123 00456
The example output has 2 lines. Compare its order, separators and whitespace with the input before copying the result.
Group case and spaces
Settings: Ignore case and Trim spaces enabled; skip blank lines enabled; unique-line export
Input:
[email protected] [email protected]
One duplicate group; the first trimmed spelling is retained.
Output:
[email protected]
Export only repeating values
Settings: Duplicate-lines export; ignore case, Trim spaces and skip blank lines enabled
Input:
apple banana apple pear
Each repeating value is exported once. Single-occurrence values are omitted.
Output:
apple
Choose the right tool
Use this tool when you need occurrence counts and the original line positions. Remove Duplicate Lines is the simpler choice when you only need a clean list; Extract Lines That Occur Only Once excludes every repeated value.
Limitations and common mistakes
- Use one value per line. A comma-separated list on one line is treated as one complete value.
- The on-screen report includes counts and positions; the selected export controls what Copy and Download produce.
- Case-insensitive grouping is useful for many lists but may be unsuitable for case-sensitive identifiers.
- Skip blank lines and Trim spaces change grouping. Review these options before comparing records.
- Grouping compares complete lines; case and whitespace settings can merge otherwise different identifiers.
Frequently asked questions
Will it sort my cleaned list?
No. Unique export preserves the order of first occurrences. Use Sort Lines afterward if you need alphabetical ordering.
Does it find repeated words inside a paragraph?
No. It compares entire lines. Place one item on each line to compare individual items.
Are line numbers from the original input?
Yes. Duplicate positions refer to original input lines, even when blank lines are skipped.
How can I locate repeated lines in text online?
Paste one value per line. Decide whether to ignore case, trim spaces or skip blank lines. Select Find duplicates and choose the export you need.
Where is my input processed?
The bundled tool processes input in your browser. It does not upload tool input to a conversion service. Other site plugins, analytics, advertising and browser extensions may have separate behavior.
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