Remove Duplicate Lines
Paste your text and instantly remove repeated lines. Supports case-sensitive matching, whitespace trimming, and sorting.
How to Remove Duplicate Lines
This free tool removes repeated lines from any text instantly. All processing happens in your browser — no data is sent to any server.
Options Explained
- Case-sensitive — When enabled, "Hello" and "hello" are treated as different lines. Disable to ignore case differences.
- Trim whitespace — Removes leading and trailing spaces from each line before comparison. This catches lines that are identical except for extra spaces.
- Sort result — Alphabetically sorts the deduplicated output. Useful for creating clean, ordered lists.
- Keep first occurrence — When enabled, the first appearance of each unique line is preserved. When disabled, all occurrences of duplicated lines are removed entirely.
Common Use Cases
- Cleaning email lists — Remove duplicate email addresses from mailing lists
- Log file analysis — Deduplicate log entries to find unique events
- Data cleaning — Remove repeated records from CSV or text exports
- Code cleanup — Remove duplicate import statements or configuration lines
- SEO keyword lists — Deduplicate keyword research exports from multiple tools
Frequently Asked Questions
The tool reads each line of your text and compares it with previously seen lines based on your chosen settings (case sensitivity and whitespace trimming). When a duplicate is found, it is removed from the output. The first occurrence of each unique line is always preserved.
Yes. All processing happens entirely in your browser using JavaScript. Your text is never sent to any server, stored in any database, or shared with third parties. The tool runs 100% client-side, so your data stays on your device.
Yes. By default, comparison is case-sensitive, so "Hello" and "hello" are treated as different lines. You can toggle the case-sensitive option off to treat lines with different capitalization as duplicates and remove the extra occurrences.
Yes. The tool preserves the original order of your text and keeps the first occurrence of each unique line in its original position. Only subsequent duplicate lines are removed. You can also enable sorting to alphabetically order the output after deduplication.
Common use cases include cleaning up email lists, deduplicating keyword research exports, removing repeated log entries, cleaning CSV or text data, removing duplicate import statements from code, and merging lists from multiple sources where overlapping entries need to be eliminated.