exit(EXIT_FAILURE) if a port was specified to the client and no pm3 is usable

client/proxmark3.c

@@ -503,6 +503,9 @@ int main(int argc, char *argv[]) {
         CloseProxmark();
     }
 
+    if ((port != NULL) && (!session.pm3_present))
+        exit(EXIT_FAILURE);
+
     if (!session.pm3_present)
         PrintAndLogEx(INFO, "Running in " _YELLOW_("OFFLINE") "mode. Check \"%s -h\" if it's not what you want.\n", exec_name);
 
@@ -531,5 +534,5 @@ int main(int argc, char *argv[]) {
         CloseProxmark();
     }
 
-    exit(0);
+    exit(EXIT_SUCCESS);
 }