Free Text Cleaning Tool
Duplicate Lines Remover
Remove duplicate, empty, and blank lines from any text in one click. Sort, trim, and clean lists, logs, data exports, and code — everything runs instantly in your browser with no text ever leaving the page.
About This Tool
What Is a Duplicate Lines Remover?
Instant text deduplication
A duplicate lines remover scans a block of text line by line and eliminates every repeated entry, keeping only the first — or last — occurrence of each unique line. No installation, no accounts, no data sent to any server.
Smart line comparison
Lines are compared with full case sensitivity by default. Switch to case insensitive mode so that "Apple" and "apple" are treated as identical, giving you precise control over exactly which lines are kept.
Combined cleanup in one pass
Beyond duplicates the tool also removes empty lines, trims leading and trailing whitespace, collapses extra blank lines, and normalises Windows and Mac line endings — saving hours on large text files and data exports.
Benefits
Why Remove Duplicate Lines?
Cleaner data exports
CSV exports, database dumps, and server log files regularly accumulate repeated rows. Removing duplicates before importing ensures data integrity and prevents constraint violations or double-counting in downstream systems.
Faster code review
Duplicate lines in config files, CSS rule sets, or import statements hide bugs and slow reviews. A clean file with no repeated entries is easier to read, diff, and maintain over time.
Tidier keyword lists
SEO keyword research tools and PPC campaign exports often produce overlapping keyword lists. Deduplicating — with optional case insensitive matching — before upload prevents wasted ad spend and duplicate targeting.
Feature Guide
Remove Empty Lines from Text
Empty vs whitespace-only lines
An empty line has zero characters. A whitespace-only line appears blank but contains invisible spaces or tab characters. Use "Remove Empty Lines" for truly zero-length lines, or "Remove Whitespace-Only Lines" to catch both with one option.
Extra blank line collapsing
The "Remove Extra Blank Lines" option preserves a single blank line between paragraphs while collapsing two or more consecutive blank lines into one — ideal for cleaning pasted content without losing all paragraph spacing.
Combined with trimming
Enable "Trim Trailing Spaces" alongside "Remove Whitespace-Only Lines" to first strip invisible trailing characters, then remove any resulting blank lines, ensuring no invisible whitespace survives the cleanup pass.
Examples
Text Cleanup Examples
SEO tools
keyword research
SEO tools
backlinks
keyword research
SEO tools
keyword research
backlinks
Line one
Line two
Line three
Line one
Line two
Line three
Apple
banana
APPLE
Banana
cherry
Apple
banana
cherry
Use Cases
Use Cases for Developers and Writers
Developers
Deduplicate import statements, CSS selectors, environment variable keys, and dependency lists. Sort and clean .gitignore entries, hosts file lines, and server config blocks.
Content writers
Remove repeated paragraphs or sentences accidentally pasted from different drafts. Clean up bullet-point lists that grew across multiple editing rounds without losing order.
Data analysts
Prepare text-based datasets before ingestion. Remove duplicate category labels, tag values, or city names exported from spreadsheets and analytics dashboards in seconds.
SEO professionals
Merge keyword lists from multiple research tools and remove exact and case insensitive duplicates in one step before uploading to Google Ads or your keyword rank tracker.
Database administrators
Clean SQL dump outputs, remove duplicate INSERT statements, and prepare normalised reference data. Use sort options to identify near-duplicates during a manual review pass.
System administrators
Deduplicate hosts entries, firewall rules, and crontab lines. Normalise line endings when merging config fragments created on Windows, Linux, and legacy Mac systems.
FAQs
Duplicate lines remover questions
Does this tool send my text to a server?
No. Every operation runs locally in your browser using JavaScript. Your text never leaves the page and nothing is stored on any remote server. The tool works offline once the page has loaded.
What is the difference between case sensitive and case insensitive mode?
In case sensitive mode (the default), "Apple" and "apple" are treated as two different lines and both are kept. In case insensitive mode both are treated as the same string and only one is retained according to the keep-first or keep-last setting.
Can I keep the last occurrence of a duplicate instead of the first?
Yes. Switch "Keep Occurrence" from "Keep First" to "Keep Last". In keep-last mode the final appearance of each duplicate line is retained and all earlier occurrences are removed from the output.
How does "Remove Extra Blank Lines" differ from "Remove Empty Lines"?
"Remove Empty Lines" removes every blank line in the text. "Remove Extra Blank Lines" only collapses runs of more than one consecutive blank line into a single blank line. This preserves paragraph spacing while eliminating accidental double or triple blank line gaps.
Can I remove duplicate words within each line?
Yes. Enable the "Remove Duplicate Words" option under Advanced. Each line is processed independently — the first occurrence of every word is kept and subsequent repetitions are removed. Word matching is case insensitive regardless of the line comparison mode setting.
What line endings does the Normalize option handle?
Normalize converts Windows CRLF (\r\n) and legacy Mac CR (\r) line endings to Unix LF (\n). This prevents false duplicates when text sourced from different operating systems is processed together in the same pass.
Is there a size limit on how much text I can process?
There is no hard limit enforced by the tool. Processing happens entirely in your browser, so practical limits depend on your device's available memory. Most modern computers handle several million lines without issue.