#!/usr/bin/perl
print "Content-type: text/html\n\n";
use strict;
use diagnostics -verbose; # Desperately seeking guidance :P

use Modern::Perl;

my @l = `ls -1b`;
my $c = 0; # toggle for odd/even lines
for (@l){
    chomp;
    my $bg = $c ? "#eee" : "#ccc";
    say qq| <p style="font-family:mono;background:$bg">$_</p> |;
    $c = 0 if $c++ == 1;
}
# use strict; with use Modern::Perl; is redundant
# keeping use strict; and commenting use Modern Perl;
# would require changing "say" to "print"