Remove Duplicate Lines — Free Online Tool
Last updated: January 2025
What is Remove Duplicate Lines?
Remove Duplicate Lines eliminates repeated lines from your text, keeping only the first occurrence of each unique line.
When to use Remove Duplicate Lines?
Use it to clean up email lists, deduplicate CSV data, remove repeated entries in logs, and tidy up any line-based lists.
How to use this tool
- 1Paste your text with duplicate lines
- 2Click 'Remove Duplicates' button
- 3Copy the deduplicated result
Examples
| Input | Output |
|---|---|
| apple banana apple cherry banana | apple banana cherry |
| (Email list with duplicates) | Clean email list without repeats |
| (CSV with duplicate rows) | Deduplicated data rows |
| line 1 Line 1 line 1 | line 1 Line 1 (case-sensitive keeps both) |
| (Log file with repeated errors) | Unique error lines only |
Rules & Behavior
- Case-sensitive by default (Line 1 ≠ line 1)
- Original order is preserved
- First occurrence of each line is kept
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Frequently Asked Questions
Is duplicate detection case-sensitive?
Yes, by default. 'Apple' and 'apple' are treated as different lines. If you want case-insensitive deduplication, convert to lowercase first.
Does it remove blank lines?
Duplicate blank lines are removed (only one blank line is kept). To remove all blank lines, use our Remove Extra Spaces or Remove Line Breaks tool.
What order are the lines kept in?
The original order is preserved — we keep the first occurrence of each duplicate line and remove subsequent duplicates.
Can I deduplicate CSV data?
Yes, paste your CSV content and duplicate rows (lines) will be removed. Note that it works on exact line matches, so partial-row duplicates won't be detected.
Is there a line limit?
No limit. Paste as many lines as you need to deduplicate.