Weird problem with is_file()

[Michelle Konzack <linux4michelle@xxxxxxxxxxxxxxx>]

Hi,

I have a code sniplet which does not work and I do not know why:

----8<------------------------------------------------------------------
  $isfile=shell_exec("ls /tmp/tdphp-vserver/SESSION_" . $_SERVER['REMOTE_ADDR'] . "_" . $_COOKIE['VSERVER_AUTHUSER'] . "_* |head -n1");

  if (is_file($isfile)) {
<snip>
----8<------------------------------------------------------------------

nothing special, and the file  is there, but the stuff with

    is_file($isfile)

is not working...  If I enter the file in place of $isfile, then  it  is
working.   Quoting of $isfile does not work too.

What have a overseen?

Oh, if you think, it is an array, no it is not, because otherwise

  if (is_array($isfile)) {

would work.

Thanks, Greetings and nice Day/Evening
    Michelle Konzack

<<attachment: signature.pgp>>