Remove Duplicate Lines — Free Online Tool
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Clean up a list by removing duplicate lines, keeping only the first occurrence of each. Useful for deduplicating emails, URLs, or any line-based data.
How to use remove duplicate lines
- 1Paste your list of lines into the box.
- 2Choose whether matching should be case sensitive and whether to trim whitespace.
- 3Click "Remove Duplicates" to get a cleaned-up list.
Frequently asked questions
Which occurrence is kept when a duplicate is found?
The first occurrence of each line is kept; later duplicates are removed.
Does it matter if lines have different capitalization?
By default matching is case sensitive, so "Apple" and "apple" are treated as different — uncheck "Case sensitive" to treat them as duplicates.
Can it handle very long lists?
Yes — there's no practical size limit since processing happens locally in your browser.