--- a/info.rst	Fri Oct 15 14:11:20 2010 +0300
+++ b/info.rst	Mon Oct 18 16:45:34 2010 +0300
@@ -17,3 +17,7 @@
     cp  $i ~/usr/share/info
     install-info  $i ~/usr/share/info/dir
   done
+
+* Remove duplicated item in dir file.
+
+  $ install-info --add-once ${info_file} /path/to/dir