From: Robert Klemme <shortcutter@...>
Date: 2011-02-14T21:10:58+09:00
Subject: Re: System calls with ` in parameters

On Mon, Feb 14, 2011 at 4:52 AM, Tanaka Akira <akr@fsij.org> wrote:
> 2011/2/10 Robert Klemme <shortcutter@googlemail.com>:
>
>> Is there also a version which would return an IO or accept a block
>> with IO parameter so we can feed something into the head of the
>> pipeline and read from the tail?
>
> % ruby -ropen3 -e '
> Open3.pipeline_w(%w[head -6c], %w[cat -n]) {|w|
>  w.write "ab\ncd\nef\n"
> }'
>     1  ab
>     2  cd
>
> % ruby -ropen3 -e '
> Open3.pipeline_r(["echo", "foo`bar`baz"], ["head","-6c"]) {|r|
>  p r.read
> }'
> "foo`ba"

Very nice!  I tried

13:09:25 Temp$ ./pl.rb
<     1 000>
<     2 001>
<     3 002>
<     4 003>
<     5 004>
13:09:31 Temp$ cat pl.rb
#!/bin/env ruby19

require 'open3'

Open3.pipeline_rw(["cat", "-n"], ["sed", "-e", 's/^.*$/<&>/']) do
|sin, sout, threads|
  th = Thread.new(sout) do |io|
    io.each_line do |l|
      puts l
    end
  end

  5.times do |i|
    sin.printf "%03d\n", i
  end

  sin.close
  th.join
end
13:09:58 Temp$

Cheers

robert


-- 
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