#!/usr/bin/perl

# https://perlmonks.org/?node_id=1230099

use strict;
use warnings;

open my $x, '<', \do { local $/; <DATA> };

my $who = fork() ? 'p' : 'c';

while( <$x> )
  {
  print "$who $_";
  }

1 while wait > 0;

__DATA__
a
b
c
d
e