rdoc update.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@20586 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/open3.rb

@@ -239,13 +239,13 @@ module Open3
   #
   #   # generate a thumnail image using the convert command of ImageMagick.
   #   # However, if the image stored really in a file,
-  #   # system("convert", "-thumbnail", "80", filename, "png:-") is better
+  #   # system("convert", "-thumbnail", "80", "png:#{filename}", "png:-") is better
   #   # because memory consumption.
   #   # But if the image is stored in a DB or generated by gnuplot Open3.capture2 example,
   #   # Open3.capture3 is considerable.
   #   #
   #   image = File.read("/usr/share/openclipart/png/animals/mammals/sheep-md-v0.1.png", :binmode=>true)
-  #   thumnail, err, s = Open3.capture3("convert -thumbnail 80 - png:-", :stdin_data=>image, :binmode=>true)
+  #   thumnail, err, s = Open3.capture3("convert -thumbnail 80 png:- png:-", :stdin_data=>image, :binmode=>true)
   #   if s.success?
   #     STDOUT.binmode; print thumnail
   #   end
@@ -548,6 +548,20 @@ module Open3
   #   # count lines
   #   Open3.pipeline("sort", "uniq -c", :in=>"names.txt", :out=>"count")
   #
+  #   # cyclic pipeline
+  #   r,w = IO.pipe
+  #   w.print "ibase=14\n10\n"
+  #   Open3.pipeline("bc", "tee /dev/tty", :in=>r, :out=>w)
+  #   #=> 14
+  #   #   18
+  #   #   22
+  #   #   30
+  #   #   42
+  #   #   58
+  #   #   78
+  #   #   106
+  #   #   202
+  #
   def pipeline(*cmds)
     if Hash === cmds.last
       opts = cmds.pop.dup