diff -r 01a8d27a0857 -r a5d8e5c7a65a lib/Tools/tty
--- a/lib/Tools/tty	Fri Dec 14 21:16:27 2007 +0100
+++ b/lib/Tools/tty	Fri Dec 14 21:22:02 2007 +0100
@@ -13,10 +13,10 @@
   echo "Usage: $PRG [OPTIONS]"
   echo
   echo "  Options are:"
-  echo "    -l NAME      logic image name (default ISABELLE_LOGIC=$ISABELLE_LOGIC)"
+  echo "    -l NAME      logic image name (default ISABELLE_LOGIC=\"$ISABELLE_LOGIC\")"
   echo "    -m MODE      add print mode for output"
   echo "    -p NAME      line editor program name"
-  echo "                 (default ISABELLE_LINE_EDITOR=$ISABELLE_LINE_EDITOR)"
+  echo "                 (default ISABELLE_LINE_EDITOR=\"$ISABELLE_LINE_EDITOR\")"
   echo
   echo "  Run Isabelle process with plain tty interaction, and optional line editor."
   echo