Answer 13.1: You can use either a glob or opendir to get the number of files. In this case, you only want to report the number of files, so you can cheat a little. Use glob with two patterns at the same time: .* to find the hidden files and * that finds the rest. Store those in @files, and mixed in that list are the virtual files, . and .., that you don’t want to count. To get the total, subtract two from the number of elements in @files:

#!/usr/bin/perl
use strict;
use warnings;

my @files = glob( '.* *' );

# don't count . or ..
my $count = @files - 2;

print "I found $count files\n";

If you didn’t use that trick, you really don’t have that much more work to do:

#!/usr/bin/perl
use strict;
use warnings;

my @files = glob( '.* *' );

# don't count . or ..
foreach my $file ( @files ) {
    next if $file =~ /^\.{1,2}$/;
    $count++;
    }

print "I found $count files\n";