php_uname Returns information about the operating system PHP was built on stringphp_uname php_uname returns a string with a description of the operating system PHP is built on. If you're just wanting the name of the operating system, consider using the PHP_OS constant. ]]> There are also some related Predefined PHP constants that may come in handy, for example: ]]> See also php_version, php_sapi_name, and phpinfo.