Diff Copy Script

A Python utility to copy only modified files from a source directory to a target directory based on modification date, with powerful filtering capabilities.

Features

• Date-based filtering: Copy only files modified after a specific date
• Directory structure preservation: Maintains original folder hierarchy
• Flexible filtering:
  • Exclude specific directories (e.g., node_modules, .git)
  • Exclude file types by extension (e.g., .log, .tmp)
  • Include only specific file types
  • Exclude specific files by name
• Automatic directory creation: Creates target directories as needed
• Overwrite support: Replaces existing files in target
• Progress tracking: Shows what's being copied
• Summary report: Displays statistics after completion

Requirements

• Python 3.6 or higher
• No external dependencies (uses only standard library)

Installation

1. Download or clone the script files to a directory
2. Ensure you have Python 3 installed:

   python --version

Configuration

Edit config.json to set up your copy operation:

{
  "source_dir": "C:/path/to/your/source/folder",
  "output_dir": "C:/path/to/your/output/folder",
  "day": 1,
  "month": 1,
  "year": 2026,
  "exclude_dirs": [...],
  "exclude_extensions": [...],
  "include_extensions": [],
  "exclude_files": [...]
}

Configuration Options

Required Fields

• source_dir: Full path to the source directory to scan
• output_dir: Full path to the target directory where files will be copied
• day: Day of the month (1-31)
• month: Month of the year (1-12)
• year: Full year (e.g., 2026)
  • Files modified after this date (year-month-day) will be copied
  • Example: "day": 15, "month": 12, "year": 2025 = files after December 15, 2025

Optional Fields

• exclude_dirs: Array of directory names to skip

  • Example: ["node_modules", ".git", "dist", "build"]
  • Matches on directory name only, not full path

• exclude_extensions: Array of file extensions to skip

  • Include the dot (e.g., ".log", ".tmp")
  • Case-insensitive matching
  • Example: [".log", ".tmp", ".cache", ".pyc"]

• include_extensions: Array of file extensions to include

  • If specified, ONLY these extensions will be copied
  • Overrides exclude_extensions
  • Leave empty [] to allow all extensions (except excluded ones)
  • Example: [".py", ".js", ".ts", ".jsx"]

• exclude_files: Array of specific filenames to skip

  • Exact filename match (case-sensitive)
  • Example: ["package-lock.json", "yarn.lock", ".env.local"]

Usage

Basic Usage

1. Edit config.json with your settings
2. Run the script:

   python diff_copy.py

Using a Different Config File

python diff_copy.py my-custom-config.json

Example Scenarios

Scenario 1: Copy Modified Python Files

Copy only Python files modified after January 1, 2024:

{
  "source_dir": "C:/projects/myapp",
  "output_dir": "C:/backups/myapp-changes",
  "modified_after_date": "2024-01-01",
  "exclude_dirs": ["__pycache__", ".git", "venv"],
  "exclude_extensions": [".pyc", ".pyo"],
  "include_extensions": [".py"],
  "exclude_files": []
}

Scenario 2: Copy All Modified Files Except Logs

Copy all modified files but exclude logs and temporary files:

{
  "source_dir": "C:/projects/webapp",
  "output_dir": "C:/deployment/webapp",
  "modified_after_date": "2024-12-01",
  "exclude_dirs": ["node_modules", "dist", ".git"],
  "exclude_extensions": [".log", ".tmp", ".cache"],
  "include_extensions": [],
  "exclude_files": ["package-lock.json", ".env.local"]
}

Scenario 3: Copy Recent Source Code

Copy source code files modified in the last week:

{
  "source_dir": "C:/dev/myproject",
  "output_dir": "C:/reviews/myproject-recent",
  "modified_after_date": "2024-12-25",
  "exclude_dirs": ["bin", "obj", "packages", ".vs"],
  "exclude_extensions": [".exe", ".dll", ".pdb", ".suo"],
  "include_extensions": [".cs", ".csproj", ".sln", ".config"],
  "exclude_files": []
}

Output Example

======================================================================
DIFF COPY SCRIPT
======================================================================
Source Directory: C:/projects/myapp
Output Directory: C:/backups/myapp-changes
Modified After: 2024-01-01
======================================================================

Scanning files...

✓ Copied: src/main.py
✓ Copied: src/utils/helper.py
✓ Copied: tests/test_main.py
✓ Copied: config/settings.json

======================================================================
SUMMARY
======================================================================
Files Processed: 156
Files Copied: 4
Files Skipped: 152
Errors: 0
======================================================================

Output directory: C:/backups/myapp-changes

Done!

How It Works

1. Load Configuration: Reads and validates config.json
2. Parse Date: Converts the date string to a datetime object
3. Scan Directory: Walks through all files in the source directory
4. Apply Filters: For each file:
   • Checks if in excluded directory
   • Checks modification date
   • Checks file extension filters
   • Checks specific file exclusions
5. Copy Files: Copies matching files while preserving directory structure
6. Report: Shows summary of operation

Troubleshooting

Error: Configuration file not found

• Make sure config.json exists in the same directory as the script
• Or specify the full path: python diff_copy.py C:/path/to/config.json

Error: Source directory does not exist

• Check that the source_dir path in config.json is correct
• Use forward slashes / or escaped backslashes \\ in paths

Error: Invalid date format

• Use format: YYYY-MM-DD or YYYY-MM-DD HH:MM:SS
• Example: "2024-01-01" or "2024-01-01 14:30:00"

No files copied

• Check that files were actually modified after the specified date
• Verify your filter settings aren't too restrictive
• Make sure include_extensions is empty [] if you want all file types

Permission errors

• Run the script with appropriate permissions
• Check that you have read access to source and write access to output directory

Tips

1. Test First: Start with a small source directory to verify your filters work correctly

2. Include vs Exclude: If you specify include_extensions, only those file types will be copied (ignore exclude_extensions)

3. Date Formats: The script accepts both date-only and date-time formats

4. Path Separators: Use forward slashes / in paths for cross-platform compatibility

5. Backup: Consider backing up your target directory before running if it contains important files

License

This script is provided as-is for free use and modification.