A duplicate line remover quickly finds and removes repeated lines in text. Common uses: cleaning up duplicate records from CSV/Excel exports, removing duplicates when merging lists, processing log files for repeated entries, cleaning copied web content, and deduplicating word lists or dictionaries.
In case-sensitive mode, 'Hello' and 'hello' are treated as different lines β both are kept. In case-insensitive mode, they are considered identical and only the first occurrence is kept. Use case-sensitive for passwords, code variables, or any data where case matters.
Count mode doesn't remove duplicates β it counts how many times each line appears. Output format: 'line content [count]'. This is useful for data analysis, like finding the most frequent IP addresses or common words.
Yes. By default, empty lines are treated as duplicates and only one is kept. If you enable 'Keep empty lines', all empty lines are preserved. Recommended when maintaining line alignment or original formatting.
This tool runs entirely in your browser. It can typically handle millions of lines smoothly. For very large files (500K+ lines), consider batch processing. No data is uploaded to any server, so there are no upload limits.