Remove Duplicate Lines

Remove duplicate lines from your text while preserving the original order. Supports case-sensitive and case-insensitive modes.

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1. Paste your text containing duplicate lines into the input area. 2. Choose between case-sensitive or case-insensitive duplicate detection using the toggle. 3. Optionally enable the trim whitespace option to ignore leading and trailing spaces during comparison. 4. Optionally enable the remove blank lines option to strip empty lines from the output. 5. Review the deduplicated output and the summary showing total lines processed, duplicates found, and unique lines remaining. 6. Click the copy button to copy the cleaned text to your clipboard.

About This Tool

The Remove Duplicate Lines tool scans your text and eliminates repeated lines, keeping only the first occurrence of each unique line. This is invaluable when cleaning up data exports, email lists, log files, or any text that contains unwanted repetition.

You can choose between case-sensitive and case-insensitive duplicate detection. In case-insensitive mode, lines like "Hello" and "hello" are treated as duplicates. The tool also offers options to trim whitespace before comparing lines and to remove empty lines entirely, giving you full control over how duplicates are identified.

The output preserves the original order of your unique lines, so the first occurrence of each line remains in its original position. The tool displays a summary showing how many lines were processed, how many duplicates were found, and how many unique lines remain. Copy the cleaned text with one click.

Frequently Asked Questions

Yes. The tool keeps the first occurrence of each unique line in its original position and removes subsequent duplicates. The relative order of unique lines is never changed.
In case-sensitive mode, "Apple" and "apple" are treated as different lines. In case-insensitive mode, they are considered duplicates and only the first occurrence is kept.
Yes. There is an option to remove blank lines along with duplicate lines in a single pass, saving you time when cleaning up text with both issues.
The tool runs entirely in your browser and can handle thousands of lines efficiently. Performance may slow with extremely large inputs (over 100,000 lines), but typical use cases work instantly.
By default, leading and trailing whitespace is included in the comparison. You can enable the "trim whitespace" option to ignore leading and trailing spaces when checking for duplicates.

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