#!/usr/bin/env perl

use strict;
use warnings;

use IPC::Run qw(run);

my $str;

my $count = 0;
while (1)
{
  $count += 10;
  $str .= "1111111111";

  run [echo => $str], '|', [grep => 'foo'];
  print "$count " unless ($count % 10000)
}