🔍 Find Duplicate Lines in Text

Professional duplicate line finder that analyzes text to identify repeated lines with advanced highlighting, statistical analysis, and multiple output formats. Perfect for code review, log analysis, data cleaning, and document editing with configurable matching options.

Text to Analyze:

Paste your text, code, log files, or any content to find duplicate lines

Case sensitive matching:

Treat "Hello" and "hello" as different lines

Case sensitive matching

Ignore leading/trailing whitespace:

Treat " hello " and "hello" as the same line

Ignore leading/trailing whitespace

Output Format:

Choose how to display the duplicate analysis results

Minimum Occurrences:

Only show lines that appear at least this many times (2-1000)

Show line numbers:

Display line numbers in the output for easy reference

Show line numbers

Color-code by frequency:

Use different colors to show how often lines are duplicated

Color-code by frequency

Include empty lines in analysis:

Count blank/empty lines as potential duplicates

Include empty lines in analysis

Duplicate Line Analysis:

🔍 DUPLICATE ANALYSIS

Found 12 Duplicate Lines in 45 Total Lines

73% unique content • 27% duplicates

📊 Analysis Statistics

Total Lines

Input Text

Unique Lines

73% of total

Duplicate Lines

27% of total

Duplicate Groups

Different patterns

✏️ Highlighted Text with Duplicates

                HIGH
                MEDIUM
                LOW
                Duplicate frequency
            
function calculateTotal() {
  let sum = 0;
  console.log("Debug info");
  for (let i = 0; i < items.length; i++) {
    sum += items[i];
  console.log("Debug info");
  }
  return sum;
}

function processData() {
  console.log("Debug info");
  return sum;
}

📋 Duplicate Groups

🔥 "console.log("Debug info");" - 4 occurrences

Lines: 3, 6, 12, 18

🔸 "return sum;" - 2 occurrences

Lines: 8, 13

🔹 "}" - 2 occurrences

Lines: 9, 14

🔧

JavaScript Required:

This duplicate line finder requires JavaScript to perform text analysis and highlight duplicate content.

How to Use This Find Duplicate Lines in Text

How to Use the Duplicate Line Finder

Step 1: Input Your Text

Paste any text into the large text area - code, log files, documents, data files, or any text content you want to analyze for duplicate lines.

Step 2: Configure Analysis Options

Case Sensitive: Check to treat "Hello" and "hello" as different lines
Trim Whitespace: Ignore leading/trailing spaces when comparing lines
Output Format: Choose how to display results (highlighted, list, statistics, or detailed)
Minimum Occurrences: Set how many times a line must appear to be considered a duplicate

Step 3: Analyze and Review Results

Click "Find Duplicates" to analyze your text. Results show duplicate lines with color coding, statistics, and line number references for easy identification and removal.

💡 Pro Tip: Use the highlighted format for visual analysis, statistics format for reports, and detailed format for comprehensive line-by-line breakdown.

How It Works

How Duplicate Line Detection Works

1. Text Preprocessing

The tool splits your input text into individual lines and applies preprocessing options like case normalization and whitespace trimming to ensure accurate matching.

2. Line Fingerprinting

Each line is processed to create a normalized fingerprint for comparison. This allows for flexible matching while preserving the original text formatting.

3. Duplicate Detection Algorithm

Using efficient hash mapping, the tool tracks line occurrences and identifies patterns that appear multiple times according to your minimum occurrence threshold.

4. Statistical Analysis

The tool calculates duplicate percentages, groups similar lines, and provides comprehensive statistics about your text's redundancy patterns.

5. Visual Presentation

Results are color-coded by frequency, with line numbers for reference, making it easy to identify and address duplicate content in your original text.

When You Might Need This

• 🔍 Code Review and Quality Analysis - Identify copy-pasted code blocks, repeated debug statements, and duplicated logic in source code files to improve code quality and maintainability
• 📋 Log File Analysis and Debugging - Find repeated error messages, warning patterns, and duplicate log entries in application logs to identify recurring issues and system problems
• 🧹 Data Cleaning and Deduplication - Clean datasets by identifying duplicate records, repeated entries, and redundant data lines in CSV files, database exports, and data processing workflows
• 📝 Document Editing and Proofreading - Find repeated paragraphs, duplicated sentences, and redundant content in documents, articles, and written content to improve clarity and conciseness
• ⚙️ Configuration File Validation - Detect duplicate configuration entries, repeated settings, and redundant parameters in config files, .env files, and system configuration documents
• 📊 Test Data Analysis - Identify duplicate test cases, repeated test data entries, and redundant testing scenarios in test suites and quality assurance workflows
• 🔧 Build Script Optimization - Find repeated commands, duplicate build steps, and redundant operations in build scripts, deployment configurations, and automation workflows
• 📈 Content Management and SEO - Detect duplicate content, repeated keywords, and redundant text blocks in web content, blog posts, and SEO optimization projects
• 🎯 Requirements and Specification Review - Identify duplicate requirements, repeated specifications, and redundant documentation entries in project requirements and technical specifications
• 🔄 Migration and Conversion Projects - Find duplicate entries and repeated data during system migrations, format conversions, and data transformation projects to ensure data integrity

Frequently Asked Questions

What types of text files can I analyze for duplicates?

You can analyze any text content including source code (JavaScript, Python, Java, etc.), log files, CSV data, configuration files, documents, and plain text. The tool supports up to 50,000 lines and 5MB file sizes for comprehensive analysis.

How does case sensitivity affect duplicate detection?

When case sensitive matching is enabled (default), 'Hello' and 'hello' are treated as different lines. When disabled, they're considered duplicates. This is particularly useful for code analysis where variable names matter, or document analysis where case doesn't matter.

What's the difference between the output formats?

Highlighted format shows your original text with duplicates color-coded by frequency. List format shows only the duplicate lines. Statistics format provides detailed analysis with percentages and counts. Detailed format includes line numbers and comprehensive grouping information.

Can I adjust the minimum number of occurrences?

Yes, you can set the minimum occurrences from 2 to 1000. Setting it to 2 finds lines that appear at least twice, while higher values find only frequently repeated lines. This helps filter out less significant duplicates in large files.

How accurate is the duplicate detection algorithm?

The algorithm is highly accurate, using exact string matching after preprocessing. It handles whitespace normalization, case sensitivity options, and empty line inclusion to provide precise results. The tool processes each line individually for 100% accuracy in identifying duplicates.