1 #!/usr/bin/perl
2 
3 # Modify the previous program to change every Fred to Wilma and
4 # every Wilma to Fred. Now input like fred&wilma should look like
5 # Wilma&Fred in the output.
6 
7 use warnings;
8 use strict;
9 use utf8;
10 
11 if (scalar(@ARGV) != 1) {
12 	die "Usage: $0 filename";
13 }
14 my $filepath = ($ARGV[0] =~ s/.[^.]*\z/.out/r);
15 open my $fh, ">", $filepath or die "Unable to write to '$filepath': $!";
16 
17 while (<>) {
18 	chomp;
19 	s/Fred/\n/ig;
20 	s/Wilma/Fred/mig;
21 	s/\n/Wilma/mig;
22 	print $fh "$_\n";
23 }