--- a/dottr.pl	Fri Oct 03 15:01:17 2014 +0200
+++ b/dottr.pl	Fri Oct 03 15:05:36 2014 +0200
@@ -1,11 +1,16 @@
 #!/usr/bin/perl
 ##$Id: dottr.pl,v ac49839c1b85 2014/10/03 12:46:32 grin $
 #
-# (c) Peter 'grin' Gervai, 2012
-# Released under CreativeCommons-Attribution-ShareAlike-3.0-Unported
+# (c) Peter 'grin' Gervai, 2012-2014
+# Released under CreativeCommons-Attribution-ShareAlike-4.0
 #
 # create .dot from racktables links
 #
+#  ./dottr.pl > map.dot
+#
+# create graphic from dot: 
+#  dot -Tpng -o map.png map.dot
+#  dot -Tsvg -o map.svg map.dot
 
 use DBI;
 use Encode;