This approach won't work. The backticks are blocking the execution and you need to provide the input. So it's a dead-lock. Better to look at perlipc. Though the most generic approach is use of pipes and forks. The "open" command with "-|" or "|-" is very convinient for this. For example 

# this makes the fork and pipes STDOUT of child to OUTPUT of parent.
my $pid = open(OUTPUT, "-|");

if($pid == 0)
{
    # we are in child now. To provide input I need another fork.
    # This time the STDIN of child is piped from INPUT of this process
+.
    my $another_pid = open(INPUT, "| another_script_or_program");
    # now check the return value and pass the input thru INPUT
    print INPUT "my input\n";
    exit(0);
}

# the main process just reads data from OUTPUT
print while(<OUTPUT>);

# do waitpid
close(OUTPUT);

[download]

In reply to Re^2: running script within a script (semi-interactive) by andal
in thread running script within a script (semi-interactive) by pogbobo

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.