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Deduplicate Lines — Remove Duplicate Lines & Keep Unique Text

Remove duplicate lines from a list. Case-sensitive toggle, trim before compare, keep first or last, optional sort.

Free No signup Client-side Privacy friendly Updated

How to use

  1. 1 Paste a list with one item per line.
  2. 2 Tune the comparison: case-sensitive, trim whitespace before compare, keep first or last duplicate.
  3. 3 Optional: sort output alphabetically.
  4. 4 Copy the deduped list.

Why use this tool

  • Original order preserved by default — no surprise sort.
  • Case-insensitive option folds Apple, apple, APPLE into one entry.
  • Trim option ignores leading and trailing whitespace differences.
  • Counter shows exactly how many lines were removed.

Frequently asked questions

Are blank lines treated as duplicates?

Yes — multiple empty lines collapse to one. If trim is on, lines that are just whitespace also fold together.

What does Keep last do?

Default Keep first drops every duplicate after the initial occurrence. Keep last drops earlier occurrences and keeps the final position — useful when later entries have more recent data.

How is the comparison done with case-insensitive?

Lines are lowercased only for the lookup key; the output preserves the original casing of the kept line.

Related tools?

Use Sort Lines to also sort the result by length or numeric value, or Filter Lines to keep only lines matching a pattern.

What is Deduplicate Lines?

A Deduplicate Lines is a tool that removes duplicate lines from a list of text. It runs in the browser and offers a case-sensitivity toggle, an option to trim each line before comparing, a choice to keep the first or last occurrence of each duplicate, and optional sorting of the result.

Features

Keep first or last

Remove repeats while preserving either the first or last occurrence of each line.

Case & trim options

Match case-insensitively and trim whitespace before comparing, with optional sorting.

100% private

Runs on your device — your text is never uploaded.

Example

Input

a
b
a
c

Output

a
b
c

Common use cases

  1. 1

    Clean up lists

    Remove duplicate emails, URLs, or keywords from a pasted list.

  2. 2

    Dedupe log lines

    Collapse repeated log entries to see unique events.

  3. 3

    Prep unique data

    Produce a distinct set of values before import or analysis.

Summary

Zerethon's deduplicate-lines tool removes duplicate lines from text in your browser, keeping the first (or last) occurrence. Options include case-insensitive matching, trimming before comparison, and optional alphabetical sorting of the result. Everything runs client-side — nothing is uploaded.

Category
Creator
Pricing
Free
Privacy
Browser-based
Signup
Not required

References

Privacy

Your data never leaves your browser unless explicitly stated. Deduplicate Lines runs entirely client-side — no server upload, no logging, no tracking of your input.

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