<?php 

function isletimsistemikontrol($zzzz){ 
if(preg_match("/windows/i",$_SERVER['HTTP_USER_AGENT'],$zzzz)){ 
echo "İşletim Sistemi Windows"; 
}else if(preg_match("/linux|gentoo|centos|redhat|ubuntu|debian|arch|mandrake|pardus|suse|backtrack|lord|freebsd/i",$_SERVER['HTTP_USER_AGENT'],$zzzz)) 
{ 
echo "İşletim Sistemi Linux"; 
}else if(preg_match("/apple|iphone|macos|snowleo|ipad/i",$_SERVER['HTTP_USER_AGENT'],$zzzz)) 
{ 
echo "İşletim Sistemi MacOsX"; 
} 
} 

echo isletimsistemikontrol($deger); 

?>