Remove duplicate lines from long text lists.
The Duplicate Line Remover removes repeated lines from any text input, returning only unique lines. It supports case-sensitive mode (Apple ≠ apple) and case-insensitive mode (Apple = apple). Common uses: cleaning mailing lists with duplicate email addresses, deduplicating scraped data, removing repeated CSS or import statements, cleaning keyword lists before SEO upload, and deduplicating log entries before analysis. The tool can preserve the original order of first appearances or sort the output alphabetically.
Yes — duplicates are removed while keeping the first occurrence of each line in its original position. The output order matches the input order, minus the removed duplicates.
Use case-insensitive for email addresses (User@Example.com and user@example.com go to the same inbox), product names (iPhone = iphone), and URLs (domain names are case-insensitive, though paths may not be). Use case-sensitive for code identifiers, file paths, and anything where case carries meaning.
Lines with leading or trailing spaces are treated as different from lines without. If your data has inconsistent spacing, clean whitespace first using the Whitespace Cleaner tool before deduplicating.