Index: bin/bitclust.rb
===================================================================
--- bin/bitclust.rb	(revision 533)
+++ bin/bitclust.rb	(working copy)
@@ -24,7 +24,12 @@
 require 'optparse'
 
 def main
-  Signal.trap(:PIPE) { exit 1 }
+  begin
+    Signal.trap(:PIPE, 'EXIT')
+  rescue ArgumentError
+    # mswin32, mingw32
+    # unsupported signal SIGPIPE
+  end
   Signal.trap(:INT) { exit 1 }
 
   prefix = nil
Index: bin/bc-rdoc.rb
===================================================================
--- bin/bc-rdoc.rb	(revision 533)
+++ bin/bc-rdoc.rb	(working copy)
@@ -17,12 +17,18 @@
 class ApplicationError < StandardError; end
 
 def main
-  Signal.trap(:PIPE, 'EXIT')
+  begin
+    Signal.trap(:PIPE, 'EXIT')
+  rescue ArgumentError
+    # mswin32, mingw32
+    # unsupported signal SIGPIPE
+  end
   Signal.trap(:INT, 'EXIT')
 
   prefix = nil
   mode = :list
   type = :name
+  rdoc_dir = nil
   parser = OptionParser.new
   parser.banner = "Usage: #{File.basename($0)} <classname>"
   parser.on('-d', '--database=PREFIX', 'BitClust database path') {|path|
@@ -34,6 +40,9 @@
   parser.on('-c', '--content', 'Prints method description') {
     type = :content
   }
+  parser.on('--rdoc-database=DIR', 'RDoc/ri database directory') {|path|
+    rdoc_dir = path
+  }
   parser.on('--help', 'Prints this message and quit.') {
     puts parser.help
     exit 0
@@ -46,8 +55,12 @@
     exit 1
   end
 
-  # use only system database
-  path = RI::Paths.path(true, false, false, false)
+  unless rdoc_dir
+    # use only system database
+    path = RI::Paths.path(true, false, false, false)
+  else
+    path = RI::Paths.path(false, false, false, false, rdoc_dir)
+  end
   reader = RI::RiReader.new(RI::RiCache.new(path))
   case mode
   when :list