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   9 <title>section 7.8.4: Command Execution</title>
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  15 <H2>section 7.8.4: Command Execution</H2>
  16
  17 page 167
  18 <p>The only thing to add to this brief description of
  19 <TT>system</TT> concerns the disposition of the executed
  20 command's output.
  21 (Similar arguments apply to its input.)
  22 The output generally goes wherever the calling program's output goes,
  23 though if the calling program has done anything with <TT>stdout</TT>
  24 (such as closing it, or redirecting it within the program with
  25 <TT>freopen</TT>),
  26 those changes will probably <em>not</em> affect the output of
  27 <TT>system</TT>.
  28 One way to achieve redirection of the command executed by <TT>system</TT>,
  29 if the operating system permits it, is to use redirection
  30 notation <em>within</em> the command line passed to
  31 <TT>system</TT>:
  32 <pre>   system("date &gt; outfile");
  33 </pre>Note also that the exit status returned by the program
  34 (and hence perhaps by <TT>system</TT>)
  35 does not necessarily have anything to do
  36 with anything printed by the program.
  37 One way to capture the output printed by the program
  38 is to use redirection, as above,
  39 then open and read the output file.
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