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Duplicate Line Remover

Instantly remove duplicate or blank lines from any block of text. Free, fast, no signup.

📝 Text Tools Free Browser-based
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Unique lines
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Cleaning Lists and Exported Data

Duplicate lines are common in data exported from spreadsheets, CRMs, scrapers and analytics platforms. This tool handles thousands of lines instantly, running entirely in your browser without uploading anything.

Case-Sensitive vs Case-Insensitive Deduplication

Case-sensitive mode treats "Paris", "paris" and "PARIS" as three distinct lines. Case-insensitive mode collapses all three into one. Use case-insensitive mode when your data may have inconsistent capitalisation — common in email addresses, domain names and keyword lists.

Common Use Cases

  • Email lists — remove duplicate addresses before sending a campaign; pair with lowercase for best results.
  • Keyword lists — deduplicate scraped keywords before importing to an SEO tool or ad platform.
  • URL lists — clean crawl exports or link reports before bulk-processing.
  • Log files — strip repeated error or event lines to surface the unique issues.
  • Dictionary or word lists — remove duplicate entries from vocabulary files or autocomplete training data.

How Deduplication Order Works

The tool always keeps the first occurrence of each line and discards all later duplicates, preserving the original ordering of the unique lines. This matches the behaviour of SQL's SELECT DISTINCT and Unix's sort -u (without the sort step). If you need alphabetical order, sort the output separately or use the Trim Whitespace option to normalise lines before comparing.

'How do I deduplicate on just part of a line — like deduplicating by domain from a list of emails?', 'a' => 'This tool deduplicates complete lines. For partial-field deduplication (e.g. one email per domain), you would need a spreadsheet function or command-line tool like awk — for example: awk -F"@" "!seen[$2]++" emails.txt'], ]" />