GlyphSiftOpen studio

Clean Text · browser-local

Remove Duplicate Lines

Deduplicate copied lists without sorting them. V1 compares trimmed lines case-sensitively, retains the first exact match, and leaves the original input untouched for audit.

Built & reviewed by GlyphSift Editorial · Last reviewed · Verified by 63 automated tests

Index state
eligible
Reviewed
2026-08-24
Input limit
5,000 graphemes
27 graphemes27 code points27 bytes
Live result

Remove Duplicate Lines

alpha
beta
gamma

Good fit

Use this tool when

  • A keyword, email, or inventory list contains repeated rows.
  • First-seen order matters.
  • You want predictable case-sensitive matching.

Keep the original

Avoid it when

  • Near-duplicates need fuzzy matching.
  • Uppercase and lowercase should count as identical.
  • Rows contain structured CSV fields with embedded line breaks.
01

Reviewed truth vectors

Examples that expose the edge cases

Inputred blue red
Outputred blue

The second exact red line is removed.

Input A A B
Output A B

Trimmed values are compared; the first original row is retained.

InputApple apple
OutputApple apple

V1 comparison is case-sensitive.

02

Transparent implementation

How it works

  1. 01

    Normalize line endings and split the input.

  2. 02

    Trim each line to build a comparison key.

  3. 03

    Keep the first key and discard later exact matches without sorting.

03

Known limitations

What the result cannot promise

Case variants are treated as different lines.

Visually identical Unicode sequences may need normalization first.

The A1 interface does not perform fuzzy matching.

04

Questions before copying

Frequently asked questions

Does it change the line order?

No. It keeps the order of each first occurrence.

Are blank lines deduplicated?

Yes. Multiple blank or whitespace-only rows share the same trimmed comparison key.

Why do two identical-looking lines remain?

They may differ by case, normalization, or invisible characters. Inspect or normalize them first.

05

Experience, expertise & trust

How we verify this tool

GlyphSift Editorial — Text-engine authors & reviewers

The GlyphSift Editorial team designs the deterministic text engine, writes each tool's examples against real Unicode edge cases, and reviews every claim before a page becomes eligible for indexing. We build and test the software we document; we do not outsource the copy to generic content mills.

Each tool page is reviewed against the same six input classes the engine is tested with — ASCII, emoji, combining marks, non-Latin scripts, empty input, and 5,000-grapheme input — and cannot become eligible if it is only a parameter variation of another page.

Automated evidence

  • Tool-contract & coverage suite30 deterministic cases

    tests/tools-30.test.mjs mirrors the ToolRunner dispatch and asserts every registered engineId returns the contracted output shape, plus a coverage guard so no tool silently drops characters.

    Run in: node --test after a production build (vinext build)
  • Rendered-HTML suite12 deterministic cases

    tests/rendered-html.test.mjs renders the deployed server bundle and asserts the Unicode-version manifest and each wave's tool markup are present in the server-rendered HTML.

    Run in: node --test against the built dist/server bundle
  • Transform & cleanup suite21 deterministic cases

    tests/transform-cleanup.test.mjs exercises each deterministic cleanup and transform action against whitespace, duplicate, ordering, casing, and HTML-to-text edge cases.

    Run in: node --test, no network, no randomness

Standards this tool follows

Continue the workflow

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