Remove Duplicate Lines
Remove duplicate lines from text, keeping unique entries with options for case sensitivity, whitespace trimming, and sorting.
Run tool
This online utility cleans text lists by finding and removing repeated newline-separated lines. When you enter a multi-line list, the tool keeps the initial instance of each distinct entry and discards later duplicates. By default, comparison ignores uppercase and lowercase differences and strips leading and trailing spaces from each line. You can enable case-sensitive evaluation when letter capitalization distinguishes separate records, or disable whitespace trimming when indentation and spacing matter. The tool maintains original list order by default, but you can turn off order preservation to sort unique lines automatically. After running the tool, the output area presents the deduplicated list alongside line counts showing unique entries retained and total duplicates removed. Blank input produces an empty output without errors. It handles plain text lines such as item lists, email addresses, URLs, and keywords directly through the form controls.
Instructions
- Paste or type your newline-separated text into the Text field.
- Adjust options for Case Sensitive matching, Keep Order, or Trim Whitespace as needed.
- Click Run to process the text list.
- Copy the unique lines and view the reported summary of retained and removed line counts.
Examples
- Input text containing duplicate items like Apple, apple, Banana, and Apple. With default settings (case insensitive, trimming enabled, order kept), the tool outputs Apple and Banana, reporting 2 unique lines and 2 removed lines.
- Input text containing indented items like ' task one', 'task one', and 'Task One'. With Case Sensitive enabled and Trim Whitespace enabled, the output retains 'task one' and 'Task One' in original order, reporting 2 unique lines and 1 removed line.
FAQ
How does the tool handle uppercase and lowercase letters?
By default, line comparison ignores letter case, treating 'Item' and 'item' as identical. If you check Case Sensitive, differently cased lines are treated as distinct entries.
What happens to spaces at the start or end of a line?
When Trim Whitespace is checked, leading and trailing spaces are stripped before comparing lines. If you uncheck it, lines are compared and preserved with their exact spacing.
Can I sort the unique lines automatically?
Yes. By default, the tool preserves the original order of lines based on their first appearance. If you uncheck Keep Order, the retained lines are sorted alphabetically.
What does the tool return if the input text is empty?
If you submit empty text, the tool completes without error, displaying an empty output and reporting zero unique and removed lines.