There are many different solutions out there (read CPAN). But for straight variable replace. I like this litte fast solution. There are certainly some more 'complete' solutions, but none matches this on for speed.

# Just hand it a hash with keys=var name, value=replace value.
# template encoding scheme is %%\s*varname\*%% 
package Template;
use strict;
require 5.004;

use Carp;

sub new {
  my $proto = shift;
  my $class = ref($proto) || $proto;
  my $path = shift;
  open(F,"<$path") or croak "Cannot open $path for read: $!";
  my $template = do { local $/; scalar <F> };
  my $self = { template => $template };
  bless $self, $class;
  return $self;
}

sub spit {
  my $self = shift;
  my $data = shift;
  my $template = $self->{template};

  foreach my $field (keys %$data) {
    my $subber = $data->{$field} || '';
    $template =~ s/%%\s*$field\s*%%/$subber/g;
  }
  # now nuke all unfilled variables
  $template =~ s/%%\s*[A-Za-z0-9_]+\s*%%//g;
  return $template;
}

1;
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code orginally inspired by J. Feinberg NYC who may or may not be a member monk

mitd-Made in the Dark
'My favourite colour appears to be grey.'