2012-12-27 I/O バッファリングについて
buffering in standard streams
http://www.pixelbeat.org/programming/stdio_buffering/
why IO::Pty and Expect modules can help to solute open2 's block?
http://stackoverflow.com/questions/12705460/why-iopty-and-expect-modules-can-help-to-solute-open2-s-block