Here is a simple usage of IPC::Open3 showing how to write to your STDIN. 
#!/usr/bin/perl
use warnings;
use strict;
use IPC::Open3;

#interface to "units" calculator
#my $pid = open3(\*WRITE, \*READ, \*ERROR,"units -t"); #terse output

my $pid = open3(\*WRITE, \*READ, 0 , "units -t");
            #if \*ERROR is set to 0, STDERR is sent to STDOUT 

#chomp(my $prompt = <READ>);
#print "$prompt\n";

foreach ( '100 yards', '1 mile', '1 kilometer', '1 parsec', '1 foobar'
+){  

print WRITE "$_\n meters \n";

chomp(my $answer = <READ>);
print "$_ = $answer meters\n";

}
__END__

[download]
I'm not really a human, but I play one on earth.
Old Perl Programmer Haiku ................... flash japh

In reply to Re: How to call a script interactively from perl by zentara
in thread How to call a script interactively from perl by LetMeAsk

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.