I want to run arbitrary system commands and process each line of output as it's generated. I have some sample code that shows how I'm trying to accomplish this using IO::Pipe. It works fine for non-interactive commands, however input prompts are not displayed until after input has been recieved. The result is that the user cannot see the prompt and does not know what they are being prompted for, or even that they are being prompted. It's as if the command writes its prompt to the pipe and then blocks for input before the prompt can be read and subsequently written to stdout.

From what I understand, calling IO::Pipe::reader with an argument causes a child process to be forked and the command to be exec'd within that child process. So even if the child process is blocking for input, that shouldn't block the parent process - unless this is a limitation of fork emulation on Win32.

So my questions are:

  1. What is causing this problem?
  2. How can I overcome this problem using my current method?
  3. Is there a better approach to my objectives?
use IO::Pipe;
use warnings;
use strict;


my $cmd = shift || "pause";

my $pipe = new IO::Pipe;

$pipe->reader($cmd);

print while (<$pipe>);


__END__

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In reply to Interactive IO with IO::Pipe on Win32 by Anonymous Monk

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