Well, I've looked unsuccessfully for an answer to this question for quite some time. Basically, I have a script that prints some output, then waits for some input, then prints some more output: kind of like the following 
##################
print "Once\n";
sleep 2;

print "Input Please? ";

$line = <STDIN>;
chomp $line;
print "You got: $line\n";

sleep 5;
print "Twice\n";


##################

[download]
I'm trying to write some perl code that basically "talks" to this program but IPC::Open2 seems to hang. I'm now trying something like the following: 
my $infile  = "/tmp/foo.in";
my $outfile = "/tmp/foo.out";
my $binary  = "./output.pl";

system("mkfifo $infile");
system("$binary < $infile > $outfile &");

open(DATA_OUT, ">$infile");
open(DATA_IN, "<$outfile");

while($line = <DATA_IN>) {
    chomp $line;
    print "Got $line\n";

    if ($line =~ /\?/) {
        print DATA_OUT, "blah\n";
    }
}

close(DATA_OUT);
close(DATA_IN);

system("rm $infile $outfile");

[download]
This seems to hang too, with the script just waiting for input before doing *anything* Is there any way I can do some IPC without having to use the Expect module? Your advice is greatly appreciated!

In reply to IPC Help by fluxrad

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.