do 'mycode.pl';

##</code><code>##

use strict;
use warnings;

my ($handle, %hash);

###### Collect template contents and change to string
open($handle, 'template.dat');
$_ = join '', <$handle>;
close($handle);

###### Some dummy values to insert in the template
$hash{'name'} = 'Theodore';
$hash{'age'} = 26;

###### Every instance of %hashkey% is replaced with 
###### the corresponding value
{
no warnings;
s/%(\w+)%/$hash{$1}/g;
}

print;