bin/grapht in grapht-0.1.7 vs bin/grapht in grapht-0.1.8

@@ -6,10 +6,16 @@
   echo "could not find phantomjs!"
   exit 1
 fi
 
 if [ "$#" -ge 1 ]; then
-  phantomjs $script $@ < /dev/stdin
+  if [ ! -t 0 ]; then
+    phantomjs $script $@ < /dev/stdin
+  else
+    echo "ERROR:"
+    echo "-- grapht was called without STDIN data."
+    exit 1
+  fi
 else
   echo "ERROR:"
   echo "-- grapht was called with unknown arguments:"
   echo "-- grapht requires an initial argument, specifying the graph type."
   exit 1