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Configuration file

(also config file)

Configuration file definition

A configuration file is a file that contains the parameters and initial settings for user applications, server processes, and operating systems (OS). The software generally reads the relevant configuration file at startup to tailor the working environment for the user.

Configuration files are usually written in plain ASCII text and are relatively simple in structure. The contents of configuration files may be edited by the software itself (to remember user profiles and preferences), the user (to enable or disable specific settings), or the system administrator (to synchronize environments across a network).

Common configuration file formats

  • INI: “INI” (short for “initialization”) files were originally used by early Windows OS versions for system and app configuration, but they were eventually phased out in favor of using the Windows Registry. Currently, INI refers to an unrelated configuration file format used by OS/2 systems.
  • Property list: “Property list” is the standard configuration file format for macOS. Its filename extension is .plist.
  • JSON (JavaScript Object Notation): A configuration file format often used by JavaScript developers, particularly popular when it comes to web development.
  • XML: A configuration file format often used for Java applications.