Duplicate Line Remover
Remove repeated lines quickly. Choose options for case sensitivity, trimming and which occurrence to keep.
Total lines
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Duplicate lines
0
Unique lines
0
Empty lines
0
About Duplicate Line Remover
Duplicate Line Remover is a fast and reliable browser-based utility designed to remove repeated lines from text. It is ideal for cleaning lists, logs, CSV exports, address lists, configuration files and any plain-text content where duplicates appear. All processing runs locally in your browser — nothing is uploaded to a server.
Key features
- Remove duplicated lines while keeping the first or last occurrence.
- Case sensitive or case-insensitive comparison.
- Optional trimming of lines before comparison to ignore stray whitespace.
- Option to remove empty lines entirely.
- Live preview to check results quickly and a download button to save the cleaned file.
Practical use cases
Developers often use this tool to tidy up pasted lists of package names, host files, or code snippets. Content editors use it to clean duplicated entries from CSV exports. Data analysts use it to deduplicate rows after a quick text export. Writers and researchers can clean lists of references or notes prior to importing into a spreadsheet.
How it works
The tool splits the input by newline characters, optionally trims and filters empty lines, and then uses a lookup set to detect duplicates. If 'Keep first occurrence' is selected the algorithm preserves the first occurrence encountered and skips later duplicates. If it is not selected the algorithm keeps the last occurrence by processing lines in reverse and reversing the result again to preserve intuitive ordering.
Tips & best practices
- If your text contains trailing spaces that should not create distinct duplicates, enable Trim lines.
- For case-insensitive cleanup, turn off Case sensitive.
- If you want a deterministic output sorted by line text, process then copy output and run it through your preferred sort utility.
- Use the Download button to export results as a UTF-8 text file for safekeeping or import into spreadsheets.