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Last updated: Tue, 19 Sep 2006


(PHP 4 >= 4.0.2, PHP 5)

php_uname --  Returns information about the operating system PHP is running on


string php_uname ( [string mode] )

php_uname() returns a description of the operating system PHP is running on. For the name of just the operating system, consider using the PHP_OS constant, but be reminded this constant will contain the operating system PHP was built on.

On Unix, the output reverts to displaying the operating system information PHP was built on if it cannot determine the currently running OS.

mode is a single character that defines what information is returned:

  • 'a': This is the default. Contains all modes in the sequence "s n r v m".

  • 's': Operating system name. eg. FreeBSD.

  • 'n': Host name. eg. localhost.example.com.

  • 'r': Release name. eg. 5.1.2-RELEASE.

  • 'v': Version information. Varies a lot between operating systems.

  • 'm': Machine type. eg. i386.

Example 1. Some php_uname() examples

echo php_uname();
echo PHP_OS;

/* Some possible outputs:
Linux localhost 2.4.21-0.13mdk #1 Fri Mar 14 15:08:06 EST 2003 i686

FreeBSD localhost 3.2-RELEASE #15: Mon Dec 17 08:46:02 GMT 2001

Windows NT XN1 5.1 build 2600

if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
    echo 'This is a server using Windows!';
} else {
    echo 'This is a server not using Windows!';


There are also some related Predefined PHP constants that may come in handy, for example:

Example 2. A few OS related constant examples

// *nix
echo PHP_SHLIB_SUFFIX;    // so
echo PATH_SEPARATOR;      // :

// Win*
echo PHP_SHLIB_SUFFIX;    // dll
echo PATH_SEPARATOR;      // ;

See also phpversion(), php_sapi_name(), and phpinfo().

Last updated: Tue, 19 Sep 2006