From: Jim Freeze <jim@...>
Date: 2001-07-11T02:57:58+09:00
Subject: [ruby-talk:17625] How to use popen with &

Hi:

I am trying to do a double pipe with popen but am not
having much luck.
From the command line I do the following:

 cat gnu_input | gnuplot | xv - &

Whe automating with Ruby, I don't want to write gnu_input into a file.
So I tried

 cmd = "gnuplot | xv - &"
 IO.popen(cmd, "w") {|f| f.puts gnu_input}

 And it fails, giving the reason as an empty temp file.
 However, if I don't put the job in the background, then
 it works. EG

 cmd = "gnuplot | xv -"
 IO.popen....

 works.

Is there a way to put xv in the background after the popen call
or another way to do this so xv starts in the background?

Thanks


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Jim Freeze
jim@freeze.org
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http://www.freeze.org
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