#!/usr/bin/env perl
use warnings;
use 5.012;

my $in_filename = 'three_Freds';
my $out_filename = 'three_Freds.out';

open my $config_fh, '<', $in_filename or die "$in_filename: $!";
open my $output_fh, '>', $out_filename or die "$out_filename: $!";

my $three_Freds = $ARGV[0];
if (! defined $three_Freds) {
	die "Usage: $0 filename";
}

while (<$config_fh>) {
	chomp;
	s/fred/\n/gi;
	s/Wilma/Fred/gi;
	s/\n/Wilma/g;
	print $output_fh $_;
}