displaydot.sh: this is sh(1) syntax.

src/conversation/displaydot.sh

@@ -1,5 +1,3 @@
-#!/bin/bash
+#!/bin/sh
 dot -Tpng `ls -tr1 /tmp/*rec*.dot | tail -1` | display /dev/stdin &
-
 dot -Tpng `ls -tr1 /tmp/*play*.dot | tail -1` | display /dev/stdin &
-