Select Code to Download

# we have @files
my $number_of_files = scalar(@files);
...
    my $modvalue = $number_of_groups % $_;
    push @{$groups[$modvalue]},$files[$_ - 1]);
}

{ my $counter = 0;
my $number_of_groups = 10;
for (@files) {
    push(@{$groups[$counter++]},$_);
    $counter = 0 if ($counter == $number_of_groups);
} }

my %groups;
push (@{$groups{substr($_,0,1)}},$_) for @files;

for (@files) {
    my $suffix = (m/\.(\w+)$/) ? $1 : 'none';
    push(@{$groups{$suffix}},$_);
}