From: Andrew Seidel <sio2usa@...>
Date: 2008-11-25T13:33:31+09:00
Subject: pipe in cmd-line text but then reset STDIN for menu

Hello,
I'm trying to make a customized pager utility that can process
file-contents piped in from the command line, equally well as a list of
provided file names.
e.g.  cat testfile | my_util.rb    or   my_util.rb  testfile

I'm having trouble using the pipe to get the file contents and still be
able to use STDIN in a non-blocking way for a shell-style interactive
menu.

For the menu, I'm using Highline::SystemExtensions:  e.g.:
while (mychar = get_character) && (mychar.chr != "q")
  if (mychar.chr == "x") then
    filter_all_but_selected
  end
end

... and that works only for the case where there is no input pipe,
instead filename(s) I get from ARGV.

Here's what I've tried to get the pipe read before begining the menu,
but thid hammers the rest of my script and my highline menu doesn't
work:

def fill_pipe
  # capture piped input
  flags = STDIN.fcntl(Fcntl::F_GETFL, 0)
  flags |= Fcntl::O_NONBLOCK
  STDIN.fcntl(Fcntl::F_SETFL, flags)
  begin
    input_pipe = STDIN.readlines
    $working_pipe.concat(input_pipe)
#    puts "Input pipe: #{$input_pipe}"
  rescue Errno::EAGAIN
    puts "ERROR: no input piped nor file name provided"
    display_help
  end  # end what kind of input
end # end fill_pipe

STDIN.close_read  doesn't do the trick to reset things -- ideas how I
can have it both ways?  Thanks!  Andrew.
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