In computing, configuration files, or config files configure the parameters and initial settings for some computer programs. They are used for user applications, server processes and operating system settings. The files are often written with ASCII encoding (rarely UTF-8) and line-oriented, with lines terminated by a newline or carriage return/line feed pair (CR LF), depending on the operating system. In operating systems that categorise files by extensions, software-dependent extensions .cnf, .conf, and .cfg are often used.