--- a/PipeStream.st	Tue May 22 18:38:10 2018 +0200
+++ b/PipeStream.st	Tue May 22 21:22:15 2018 +0200
@@ -209,11 +209,14 @@
                                                     [exEnd]
 
   bidirectional:
+  (must add a '-u' argument, because otherwise sed will read a big junk
+  waiting for more input, before generating any output) 
+  Notice: OSX sed does not support a '-u' option (sigh)
                                                     [exBegin]
     |p|
 
     p := PipeStream bidirectionalFor:'sed -u -e s/Hello/Greetings/'.
-    p nextPutLine:'bla'; flush.
+    p nextPutLine:'bla'.
     Transcript showCR:p nextLine.
     p nextPutLine:'foo Hello'.
     Transcript showCR:p nextLine.