Hello

I want to make some additional checks under authorization.
I edited default file in preprocess section.
This is how I want to make it:

   preprocess


if (%{exec:/path/to/script.sh} == "some numbers"){
                                        update control {
                                        Auth-Type := "Accept"
                                                        }
                                     }
            else {
                    update control {
                                         Auth-Type := "Reject"
                                                        }
                                   }

However this doesn't work.
Debug shows:
Bare %{...} is invalid in condition at: %{exec:/path/to/script.sh} == "some numbers")
 What im doing wrong ?
Is there possibility to execute remote script in this place ?