On line 33 your uninitialized variable was $new_kids. So I looked for that, and I had to wonder if you really meant to write: 
sub interact() {
    print 'Current number of children is: ', "$children", '. i.e. thes
+e:', "\n\n"; 
    system('ps -ef | grep tryMore | grep -v grep');
    print "\n\n";
    print 'Minus one for the parent, of course', "\n\n"; 
    print 'How many children do you want to add? [1]: ';
    my $new_kids = <>;
#   ^^ (Your mistake?)
    chomp $new_kids;
    $new_kids = '0' unless $new_kids;
    unless($new_kids) { $children += 1; } else { $children += $new_kid
+s; }
    return; 
}

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UPDATE
In response to the note below. Experience consists of recognizing a mistake the second time we make it. *Learning* is when you can recognize that someone else is making the mistake. When I can answer questions fast, it usually is a good sign that I have spent an hour or more making that very mistake in my own code...

In reply to Re (tilly) 1: our + redo = ??? by tilly
in thread our + redo = ??? by jptxs

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