What's the difference between case-sensitive and case-insensitive?

Case-sensitive treats 'Hello' and 'hello' as different lines (both are kept). Case-insensitive treats them as the same line (only one is kept). Enable case-insensitive if you want to remove duplicates regardless of capitalization.

Will the tool preserve the original line order?

Yes, the tool preserves the original order of unique lines. When duplicates are removed, the first occurrence of each unique line is kept in its original position. Other occurrences of the same line are removed.

Can I remove duplicates based on partial matches?

No, this tool only removes exact duplicate lines. Lines must match exactly character-by-character. For partial matching or fuzzy deduplication, use specialized data cleaning tools or preprocess text to normalize before removing duplicates.

What happens if lines have different whitespace?

Lines with different whitespace are treated as different lines. 'text', ' text' (with leading space), and 'text ' (with trailing space) are all considered unique. To remove these as duplicates, normalize whitespace first (trim spaces) before processing.

Can I keep the last occurrence instead of the first?

Yes! Use the 'Keep Last Occurrence' option. By default, the first occurrence of each unique line is kept. With this option enabled, the last occurrence is kept instead, and earlier occurrences are removed.

Remove Duplicate Lines - Clean Text Free

When to Use This Tool

Use this when:

You have email lists or contact databases with duplicate entries that need to be cleaned
You want to remove duplicate lines from log files or data exports
You have text documents or code files with repeated lines that need to be removed
You need to clean duplicate entries from CSV data before importing to databases
You want to remove duplicate lines from lists or inventories for data cleaning
You have text files with accidental duplicate content that needs to be deduplicated
You're preparing data for analysis and need to remove duplicate records

Don't use this if:

You need to remove duplicates from very large texts (over 100,000 lines may process slowly)
You want to remove duplicates based on partial matches or fuzzy matching (this tool requires exact line matches)
You need to preserve duplicate lines but mark them (this tool removes duplicates entirely)
You require advanced deduplication with custom logic or rules (use specialized data cleaning tools)
You want to remove duplicates from structured data with specific field matching (use database tools)

What is a Duplicate Line Remover?

A duplicate line remover identifies and removes repeated lines from text, keeping only unique entries. Our tool processes everything in your browser — your text data never leaves your device.

Removing duplicate lines is a common data cleaning task: deduplicating email lists, cleaning up log file outputs, removing repeated entries from CSV data, consolidating keyword lists, and cleaning up configuration files with repeated entries.

This tool is essential for data analysts cleaning up datasets before analysis, marketers deduplicating email and contact lists, DevOps engineers cleaning log file outputs, SEO specialists consolidating keyword research lists, and developers cleaning up test data or configuration files.

Compared to using spreadsheet formulas (complex setup with UNIQUE() and helper columns), command-line tools like sort -u (which reorders lines) or awk (requires knowledge of the language), or text editors with find-and-replace (tedious for large files), PureXio's tool removes duplicates instantly while preserving the original line order.

The tool offers options to preserve or discard the original order, perform case-sensitive or case-insensitive comparison, trim whitespace before comparison, show a count of how many duplicates were removed, and handle large text blocks with thousands of lines efficiently. Results can be copied to clipboard or downloaded as a text file.

Best for: removing duplicate lines from text and lists. Preserves order, case-sensitive/insensitive modes, whitespace handling. Handles large datasets. Fully private.

How to Remove Duplicate Lines

Paste text with duplicate lines into the input field. Each line is analyzed for duplicates

Choose options: Case sensitive (treats 'Hello' and 'hello' as different) or case insensitive (treats them as same). Choose to keep first or last occurrence of duplicates

Click 'Remove Duplicates' to process. Copy cleaned text with duplicates removed. Original line order is preserved for unique lines

Common Use Cases

Remove duplicate entries from email lists or contact databases for mailing lists

Clean duplicate lines from log files or data exports before analysis

Remove repeated lines from text documents or code files

Clean duplicate entries from CSV data before importing to databases

Remove duplicate lines from lists or inventories for data cleaning

Deduplicate text files with accidental duplicate content

Clean contact lists or directories by removing duplicate entries

Features

Remove duplicate lines from text while preserving original order

Case-sensitive or case-insensitive duplicate detection

Option to keep first occurrence or last occurrence of duplicate lines

Statistics display: shows original line count, duplicate count, and final line count

Real-time processing—results appear instantly

Works with any text length (small lists to large data files)

100% private—all processing happens in your browser

Limitations & Constraints

Only removes exact duplicate lines—lines with slight differences (spaces, punctuation) are kept

Case-sensitive comparison by default—'Hello' and 'hello' are treated as different unless case-insensitive option is enabled

Whitespace differences create separate lines—'text' and ' text' (with leading space) are treated as different

Very long texts (>100,000 lines) may process slowly—consider splitting into smaller sections

Line order affects which duplicate is kept—first occurrence is preserved by default

Troubleshooting

Duplicates not removed or some duplicates remain

Solution: Check if lines are exactly identical—even spaces, tabs, or case differences prevent removal. Lines must match exactly character-by-character. Enable case-insensitive option if you want 'Hello' and 'hello' to be treated as duplicates. Normalize text first (trim whitespace, convert case) if needed. Prevention: Normalize text formatting before removing duplicates if you want to ignore whitespace or case differences.

Wrong lines removed or first occurrence not kept

Solution: First occurrence of each line is kept by default. If you need different logic, use the 'Keep Last Occurrence' option to keep the last duplicate instead. The tool processes lines in order, so the first unique line encountered is preserved. Prevention: Understand that the tool keeps the first occurrence of each unique line—adjust options if you need different behavior.

Processing is slow or browser becomes unresponsive

Solution: Very long texts (>50,000 lines) process slowly. Split text into smaller chunks (10,000-20,000 lines at a time) and process separately, or wait for processing to complete. Close other browser tabs to free up resources. For extremely long texts, use desktop software. Prevention: Process text in smaller sections if it's very long.

Need case-insensitive removal but duplicates still remain

Solution: Enable the 'Case Insensitive' option—this treats 'Hello' and 'hello' as the same line. Without this option, case differences prevent duplicate removal. Also check for whitespace differences—'text' and 'text ' (with trailing space) are different. Normalize whitespace first if needed. Prevention: Enable case-insensitive option if you want to ignore case differences.

Whitespace causing issues or duplicates not detected

Solution: Lines with different whitespace are treated as different. 'text', ' text' (leading space), and 'text ' (trailing space) are all different. Trim whitespace from lines first, or normalize spacing before removing duplicates. The tool requires exact character-by-character matches. Prevention: Normalize whitespace before processing if you want to ignore spacing differences.