You might like to consider using a a templating system such as HTML::Template. Consider:

use strict;
use warnings;
use HTML::Template;

# Create a sample file - for demo purposes only
open OUTFILE, '>', 'sample.tmpl';
print OUTFILE <<HTML;
<p>The password is: <TMPL_VAR NAME='password'></p>
HTML
close OUTFILE;

# Here be the important sample code
my $template = HTML::Template->new (filename => 'sample.tmpl');

$template->param (password => 'wibble');
print $template->output ();
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Prints:

<p>The password is: wibble</p>
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