catnip is a high-performance Rust CLI tool designed to simplify project understanding and code modification workflows. It concatenates multiple files into a single, well-formatted markdown document and provides automated code patching capabilities using regex-based updates.

• 📂 Comprehensive Directory Mapping

  • Generates a visual tree representation of project structure
  • Supports recursive file discovery
  • Intelligent file and directory exclusion with comprehensive default patterns

• 🔍 Advanced File Processing

  • Supports 50+ programming languages and file types
  • Automatic syntax highlighting in code blocks
  • Binary file detection and exclusion
  • Optional comment and docstring removal
  • Configurable file size limits

• 🔧 Automated Code Patching

  • JSON-based patch specification system
  • Exact string matching for precise code updates
  • Multi-file batch operations
  • Safe replacement with backup options

git clone <repository-url>
cd catnip
cargo build --release
cargo install --path .

Make sure the binary is in your PATH.

# Process files and output to stdout
catnip cat src/main.rs src/lib.rs

# Process entire directory
catnip cat src

# Append prompt for JSON updates to be used with catnip patch
catnip cat --prompt src

# Save to file
catnip cat src -o project_summary.md

# Exclude additional patterns
catnip cat . --exclude "*.log" --exclude "temp/*"

# Include only specific patterns
catnip cat . --include "*.rs" --include "*.toml"

# Remove comments and docstrings
catnip cat src --ignore-comments --ignore-docstrings

# Set maximum file size (default: 10MB)
catnip cat . --max-size-mb 5

# Apply patches from JSON content in the clipboard
catnip patch

# Apply patches from JSON file
catnip patch updates.json

# Apply patches with dry-run (preview changes)
catnip patch updates.json --dry-run

# Create backups before applying patches
catnip patch updates.json --backup

• <PATHS>...: One or more files or directories to process
• -o, --output <FILE>: Optional output filename
• -e, --exclude <PATTERN>: Additional patterns to exclude
• -i, --include <PATTERN>: Additional patterns to include
• --ignore-comments: Strip code comments from output
• --ignore-docstrings: Remove docstrings from output
• --max-size-mb <SIZE>: Maximum file size in MB (default: 10)
• -p, --prompt: Include prompt instructions for LLM analysis

• <JSON_FILE>: JSON file containing patch specifications
• --dry-run: Preview changes without applying them
• -b, --backup: Create backup files before modifications

{
  "analysis": "Brief description of changes being made",
  "files": [
    {
      "path": "src/main.rs",
      "updates": [
        {
          "old_content": "fn old_function() {\n    println!(\"old implementation\");\n}",
          "new_content": "fn new_function(param: &str) {\n    println!(\"Updated: {}\", param);\n}",
          "description": "Replace old_function with improved version"
        }
      ]
    }
  ]
}

The tool automatically excludes:

• Build artifacts: *.pyc, *.o, *.class, target/, build/, dist/
• Dependencies: node_modules/, __pycache__/, .venv/, venv/
• Version control: .git/, .svn/, .hg/, .bzr/
• System files: .DS_Store, Thumbs.db, *.tmp, *.bak
• Media files: *.jpg, *.png, *.mp4, *.zip, *.tar
• IDE files: .vscode/, .idea/
• Logs and databases: *.log, *.sqlite, *.db
• Lock files: Cargo.lock, package-lock.json, yarn.lock
• Certificates: *.pem, *.key, *.crt

Automatically includes common development files:

• Programming languages: *.rs, *.py, *.js, *.ts, *.java, *.go, *.cpp, *.c, *.h
• Web technologies: *.html, *.css, *.scss, *.vue, *.svelte
• Configuration: *.json, *.yaml, *.toml, *.ini, *.conf
• Documentation: *.md, *.txt, README*, CHANGELOG*
• Build files: Cargo.toml, package.json, Makefile, Dockerfile*
• Scripts: *.sh, *.bash, *.ps1, *.bat
• Database: *.sql, *.pgsql

The tool recognizes and provides syntax highlighting for 40+ languages including:

• Systems: Rust, C, C++, Go
• Web: JavaScript, TypeScript, HTML, CSS, Vue, Svelte
• Backend: Python, Java, C#, PHP, Ruby
• Mobile: Swift, Kotlin, Dart
• Functional: Scala, Clojure, F#
• Scripting: Bash, PowerShell, Lua, Perl
• Data: SQL, R, YAML, JSON

The cat command generates a structured markdown document with:

1. Project Structure: ASCII tree representation of directories and files
2. File Contents: Each file's content in appropriately highlighted code blocks

1. Analyze codebase:

   catnip cat src/ > codebase.md

2. Get LLM recommendations (using the generated markdown)

3. Create patch file (following JSON format)

4. Apply changes:

   catnip patch updates.json --dry-run  # Preview
   catnip patch updates.json --backup   # Apply with backup

• RUST_LOG: Set logging level (error, warn, info, debug, trace)