That was what I thought, but interestingly, I didn't get the prompt back through $reader, Hm.. where did it go?

If I can get it, the whole thing is resolved.

Update:

  1. tye's suggestion definitely makes sense, as it might be just the prompt is not flushed yet. But I tried this: 
    #!/usr/bin/perl

use IPC::Open2;
use strict;

my ($reader, $writer);
my $pid = open2($reader, $writer, "sh") || die "failed";

print $writer "history\n";
my $buffer;
sysread($reader, $buffer, 4000);
print "[", $buffer, "]\n";

print $writer "ls\n";
sysread($reader, $buffer, 4000);
print "[", $buffer, "]\n";

    [download]
    There is no prompt being printed between two prints. So it means/proves that the prompt is NOT THERE, doesn't matter what it is, but I do like tye's suggestion, it is 100% logical.

  2. I did a research, and someone said on internet that sh does not output prompt if it is not used interactively. This matches my result.

    But is there a switch to toggle this feature?

In reply to Re: (Expect) Re: question for open2, and by the way, resolves an old thread by pg
in thread question for open2, and by the way, resolves an old thread by pg

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