How it works
Keep the first occurrence of each exact, case-sensitive line; preserve order
Input definitions
- Lines
- Plain text; maximum 200,000 characters.
A worked example
- Lines
- a b a
a
b
Assumptions & limits
Unicode plain text only. No input is uploaded. Maximum 200,000 characters.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-17. Content checked against the stated method and examples. Our verification approach.
Common questions
Can I paste formatted documents into this text tool?
The tool processes plain text. Styling, document structure and rich-text metadata are not preserved. Copy the result before closing the page.
How does the Remove duplicate lines tool work?
Keep the first occurrence of each exact, case-sensitive line; preserve order.
What are the assumptions and limits of Remove duplicate lines?
Unicode plain text only. No input is uploaded. Maximum 200,000 characters.