How do I remove duplicate lines online?

Paste your text, check 'Remove duplicate lines', and click Clean. The tool removes all repeated lines, keeping the first occurrence. Optionally sort them first for a clean deduplicated list.

How do I remove blank lines from text?

Check 'Remove empty/blank lines' and click Clean. Lines containing only whitespace are also removed when 'Trim lines' is enabled.

Line Cleaner — Remove Duplicates, Empty Lines, Comments

The Line Cleaner tool is a Swiss-army knife for processing text files line by line. Whether you're deduplicating a list of email addresses, cleaning up a CSV file, removing commented-out code, or tidying up a word list, this tool handles the most common line-level operations instantly in your browser.

What You Can Do

Remove duplicate lines — keep the first occurrence of each unique line
Remove empty lines — strip blank lines or lines containing only whitespace
Remove comment lines — strip lines starting with #
Trim lines — remove leading and trailing whitespace from each line
Sort alphabetically — arrange lines in A–Z order
Reverse order — flip the order of lines
Add line numbers — prefix each line with its number
Case-insensitive deduplication — treat "Hello" and "hello" as duplicates

Frequently Asked Questions

What counts as a duplicate line?

By default, two lines are duplicates if they are byte-for-byte identical (case-sensitive). Enable case-insensitive mode to deduplicate regardless of letter case. Trimming lines before deduplication removes whitespace differences.

Can I process files larger than a few MB?

Yes — all processing runs in your browser's JavaScript engine, which can handle millions of lines without a server. For very large files, paste the content directly into the text area.

Line Cleaner online

Remove duplicate lines, empty lines, and clean up text — runs in your browser

What You Can Do

Frequently Asked Questions

What counts as a duplicate line?

Can I process files larger than a few MB?