Duplicate Line Remover
Remove duplicate lines from text instantly. Keep the first occurrence of each unique line. Optional case-sensitive comparison, trim whitespace from each line, and remove blank lines. All processing in your browser — no data is sent to any server.
Table of Contents
What is a Duplicate Line Remover?
A duplicate line remover takes text split into lines and removes repeated lines, keeping only the first occurrence of each unique line. It is useful for cleaning lists, log files, CSV data, or any line-separated text where duplicates are unwanted.
This tool processes your text entirely in your browser. No data is sent to any server, so it is safe for sensitive or private content.
How it Works
- Paste or type your text into the input field. Each line is treated as one item.
- Set options: Case sensitive, trim whitespace from each line, and/or remove blank lines.
- View the result in the output field. The first occurrence of each unique line is kept; later duplicates are removed.
- Copy the result with one click. The output updates as you type or change options.
Line endings (\n, \r\n, \r) are normalized so lines are compared correctly.
Options
- Case sensitive: When on, "Apple" and "apple" are different (both kept). When off, they are treated as the same (first occurrence kept).
- Trim whitespace from each line: When on, leading and trailing spaces are removed from each line before comparison, so " foo " and "foo" are treated as the same; output lines are trimmed.
- Remove blank lines: When on, empty lines are removed from the output before or as part of duplicate removal.
Common Use Cases
- Lists: Clean contact lists, email lists, or tag lists by removing duplicate entries.
- Logs: Reduce repeated lines in log output for easier reading.
- CSV / data: Remove duplicate rows (one value per line or paste one column).
- Code: Deduplicate import lists, config entries, or line-based data.
- Keywords: Remove duplicate keywords or phrases for SEO or content analysis.
Frequently Asked Questions
The first occurrence of each unique line is kept. All later duplicates are removed. Order of unique lines is preserved.
When Trim whitespace from each line is on, leading and trailing spaces
and tabs are removed from each line before comparing. So foo and foo are treated as the same line — only the first is kept,
and the output line is trimmed. Use this when your lines may have accidental spaces.
When case sensitive is on, "Apple" and "apple" are different — both stay. When off, they are treated as the same line — only the first (e.g. "Apple") is kept.
No. All processing happens in your browser. Your text never leaves your device.