What is Duplicate Line Remover?

Duplicate Line Remover strips repeated lines out of any text. Paste a list, log file, or dataset and get back only the unique lines, kept in the original order or sorted A–Z, Z–A, by length, or shuffled.

Lines are matched after optional trimming and case-folding, so 'Apple', 'apple ', and ' apple' collapse into one entry when you turn those switches on. The Before pane highlights every duplicate group with a counter so you can verify which entries are getting merged. Set Keep to Drop all repeats to keep only the lines that appear exactly once. There's no row limit, and you can paste text or load a .txt or .csv file straight from your device — nothing is uploaded.

How to use

1. Paste or type your text with duplicate lines into the input area.
2. Set your options: case-sensitive or case-insensitive matching, trim whitespace, keep the first or last copy, and pick a sort order for the output.
3. The cleaned text updates live as you type — no button to press. Watch the Before, After, and Removed panels side by side, check the frequency table, then copy or download the result.

When to use

• Cleaning a CSV column where the same customer keeps appearing under slightly different rows.
• Trimming a 10,000-line log file down to the unique error messages before triage.
• Merging email lists from multiple events without sending duplicates the same announcement.

Result

A developer pastes 500 log entries containing repeated error messages and reduces them to 47 unique lines, making the actual issues immediately visible.

FAQ

Does it preserve the order I pasted the lines in?

Set Sort output to Original order and the first copy of each line stays exactly where you pasted it. Switch it to A → Z, Z → A, by length, or random shuffle to reorder the unique lines instead — alphabetical is handy before a diff or a commit. Prefer the latest copy of each line? Turn on Keep Last Occurrence.

How does case sensitivity actually work here?

With Case Sensitive on, 'Apple' and 'apple' are two different lines. Turn it off to treat them as the same. Case-insensitive matching keeps whichever casing appears first, so the output preserves your original styling.

What does Trim Whitespace do?

It strips leading and trailing spaces and tabs before comparing lines. ' hello ' and 'hello' become a match. Internal spaces are untouched, so 'hello world' (two spaces) stays distinct from 'hello world' (one space).

Can I keep only the lines that appear more than once?

Not as the main output, but the Removed panel on the right lists every discarded line with its original line number, so you can read or copy the duplicates directly without hunting through the Before pane. For the opposite job — keeping only lines that appear exactly once — switch Keep to Drop all repeats.

Is there a length limit on what I can paste?

No hard cap. Tested with files over a million lines; performance depends on your device. The text never leaves your machine, so even confidential lists are safe to process here.

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