A fully configurable Go CLI tool for managing copyright headers in source code files.

• Fully configurable: Define any copyright format via templates
• Optional licensing: Enable/disable SPDX license headers
• Path filtering: Include/exclude files using powerful glob patterns with ** support
• Multiple file types: Support any file extension with custom comment styles
• Smart detection: Skip generated files, replace specific patterns
• Third-party copyright handling: Configure how to handle existing third-party copyrights
• Git integration: Only processes git-tracked files
• Progress tracking: Visual progress bar for large codebases
• Template-based: Use Go templates for flexible header formats

go install github.com/YakDriver/copyplop@latest

Create .copyplop.yaml in your project root:

copyright:
  holder: "Your Company"
  start_year: 2020
  current_year: 2025
  format: "Copyright {{.Holder}} {{.StartYear}}-{{.CurrentYear}}"
  
license:
  enabled: true
  identifier: "MIT"
files:
  extensions: [".go", ".js", ".py", ".sh"]
  comment_styles:
    ".go": "//"
    ".js": "//"
    ".py": "#"
    ".sh": "#"

detection:
  skip_generated: true
  generated_patterns: ["Code generated", "DO NOT EDIT"]
  replace_patterns: ["Copyright.*OldCompany"]

third_party:
  action: "above"  # "leave", "above", "below", "replace"
  patterns:
    - "Copyright.*Oracle"
    - "Copyright.*Microsoft"

Configure how to handle existing third-party copyrights with precedence logic:

• leave: Keep third-party copyrights as-is, add your copyright normally
• above: Add your copyright above third-party copyrights
• below: Add your copyright below third-party copyrights
• replace: Replace third-party copyrights with your copyright

Replacement patterns take precedence over third-party patterns. This allows you to use general third-party patterns without accidentally treating your own replacement targets as third-party.

detection:
  # These get REPLACED (highest precedence)
  replace_patterns:
third_party:
  action: "above"
  # General pattern - but won't match HashiCorp due to precedence
  patterns:
    - "Copyright.*[a-zA-Z0-9].*"

Result: HashiCorp copyrights get replaced, all other copyrights are treated as third-party.

Original file with Oracle copyright:

//Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.

package main

With action: "above":

// Copyright IBM Corp. 2014, 2025
//Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.

package main

With action: "below":

//Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
// Copyright IBM Corp. 2014, 2025
package main

Handle template files that could contain different content types using smart content detection:

files:
  # Regular extensions with known comment styles
  extensions: [".go", ".py", ".md"]
  
  # Smart extensions detect content type automatically
  smart_extensions: [".gtpl", ".tmpl"]
  
  comment_styles:
    ".go": "//"
    ".py": "#"
    ".md": "<!--"

Smart extensions analyze file content to determine the actual file type:

• .gtpl (Go templates) - Could be Go code, Markdown, HCL, YAML, etc.
• .tmpl (Generic templates) - Detects the underlying content type

Binary File Safety: Files with null bytes are automatically skipped to prevent processing binary content.

# For terraform-provider-aws templates
smart_extensions: [".gtpl", ".tmpl"]

# Templates will be processed with appropriate comment style:
# - service.go.gtpl → detected as Go → uses "//" comments  
# - README.md.tmpl → detected as Markdown → uses "<!--" comments
# - main.tf.gtpl → detected as HCL → uses "#" comments

Fallback: Unknown content defaults to Go (configurable per project needs).

Control which files to process using include/exclude patterns with full doublestar glob support:

files:
  # Only process specific paths
  include_paths:
    - "internal/service/[a-g]*"     # Services starting with a-g
    - "cmd/**"                      # All files under cmd/
    
  # Skip specific paths  
  exclude_paths:
    - ".github/**"                  # Skip all GitHub workflows
    - "internal/service/s3*"        # Skip S3-related services
    - "**/*_test.go"               # Skip all test files

• No filters: Process all files
• Include only: Process only matching files
• Exclude only: Process all except matching files
• Both: Process files that match includes AND don't match excludes

• * - Single-level wildcard
• ** - Recursive directory matching
• [a-g] - Character ranges
• {foo,bar} - Alternatives
• internal/service/* - Auto-expands to match subdirectories

# Process only EC2 and ECS services
include_paths: ["internal/service/ec[2s]*"]

# Skip generated and test files
exclude_paths: ["**/*generated*", "**/*_test.go"]

# Process infrastructure code only
include_paths: ["internal/**", "cmd/**"]
exclude_paths: [".github/**", "examples/**"]

Copyplop supports configurable placement exceptions for cases where copyright headers cannot be the first line in a file.

files:
  placement_exceptions:
    xml_declaration: true    # Allow <?xml version="1.0"?> before copyright
    markdown_heading: true   # Allow # Heading before copyright  
    frontmatter: ["md", "html.md"]  # YAML frontmatter extensions

Always Enabled:

• Shebang (#!/bin/bash) - Always detected and preserved

Configurable Exceptions:

• XML Declaration - <?xml version="1.0"?> and similar
• Markdown Heading - # Title as first line
• YAML Frontmatter - Between --- markers

Exceptions are processed in this order:

1. Shebang (always)
2. XML Declaration (if enabled)
3. YAML Frontmatter (if configured)
4. Markdown Heading (if enabled)
5. Copyright header placement

XML File:

<?xml version="1.0"?>
<!-- Copyright 2024 Your Corp -->

<root>content</root>

Markdown File:

# My Document
<!-- Copyright 2024 Your Corp -->

Content here...

Backward Compatibility: The below_frontmatter configuration is deprecated. Use placement_exceptions.frontmatter instead.

# Check for issues
copyplop check

# Fix copyright headers
copyplop fix

# Process specific path
copyplop check --path ./internal/service/ec2

# Demo progress bar
copyplop demo

Available in copyright.format:

• {{.Holder}} - Copyright holder
• {{.StartYear}} - Starting year
• {{.CurrentYear}} - Current year

Available in license.format:

• {{.Identifier}} - License identifier

copyright:
  format: "Copyright {{.Holder}} {{.StartYear}}, {{.CurrentYear}}"

Output: // Copyright IBM Corp. 2014, 2025

copyright:
  format: "Copyright (c) {{.Holder}}"

copyright:
  format: "Copyright {{.CurrentYear}} {{.Holder}}"

Output: // Copyright 2025 Acme Corp

See examples/ directory for complete configurations.