Penglab Lines

Remove Duplicate Lines

Keep the first occurrence of each line and remove repeated entries.

Lines

Unique lines

Quick guide

What this tool does

Remove repeated lines from multiline text while preserving the first occurrence of each entry.

How to use it

Paste line-based content such as IDs, links, or values, remove duplicates while keeping first occurrences, and copy the unique list.

When this tool is useful

Deduplicate copied lists of emails, IDs, URLs, or filenames. Clean repeated log lines or pasted records before further processing. Reduce duplicate values before sorting, comparing, or importing data.

Common use cases

Deduplicate copied lists of emails

Deduplicate copied lists of emails, IDs, URLs, or filenames.

Clean repeated log lines or

Clean repeated log lines or pasted records before further processing.

Reduce duplicate values before sorting

Reduce duplicate values before sorting, comparing, or importing data.

Example input and output

Example input

apple
banana
apple

Expected output

apple
banana

FAQ

Which duplicate line is kept?

The tool keeps the first occurrence of each exact line and removes later repeats.

Does it trim whitespace automatically?

No. Lines are compared exactly, so leading or trailing spaces still make lines different.

Does Unique Lines run in the browser?

Yes. Unique Lines works in the browser so you can enter data, review the result, and copy the output without needing a separate desktop app.

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