What is INI?

INI (.ini) files contain configuration settings in a simple text format with sections denoted by square brackets [Section] and key-value pairs like "key=value". Comments start with semicolon (;) or hash (#). INI files are easy to read and edit by both humans and programs.

Despite being an informal standard without official specification, INI files are used across Windows applications, PHP configurations (php.ini), Git configurations, and many other software tools.

Did you know? The Windows Registry was introduced to replace INI files, but INI format persists due to its simplicity!

History

INI files originated with MS-DOS and early Windows versions as a way to store application settings. The format became a de facto standard for configuration despite never being formally standardized.

Key Milestones

  • 1980s: Introduced in MS-DOS
  • 1990: Windows 3.0 uses win.ini and system.ini
  • 1995: Windows 95 introduces Registry (but INI persists)
  • 2000s: Adopted by cross-platform applications
  • Present: Still used for configuration (PHP, Git, etc.)

Key Features

Core Capabilities

  • Sections: Organize settings with [Headers]
  • Key-Value Pairs: Simple key=value format
  • Comments: Semicolon or hash prefixes
  • Human-Readable: Plain text format
  • Simple Parsing: Easy to implement
  • Cross-Platform: Works everywhere

Common Use Cases

App Settings

Software configuration

PHP Config

php.ini settings

Git Config

.gitconfig files

Game Settings

Save game configuration

Advantages

  • Extremely simple format
  • Human-readable and editable
  • Easy to parse and generate
  • No external dependencies
  • Widely supported
  • Comments for documentation

Disadvantages

  • No official standard (variations exist)
  • Limited data types (strings only)
  • No nested structures
  • No support for arrays/lists
  • Encoding issues possible

Technical Information

Format Specifications

Specification Details
File Extension .ini
MIME Type text/plain
Format Type Configuration
Encoding ASCII or UTF-8
Structure Sections and key-value pairs
Comments ; or # prefix

Common Tools

  • Editors: Any text editor
  • Parsers: ConfigParser (Python), ini_set (PHP)
  • Validators: Manual review