This is fraught with danger, dont do this, use a template system like Text::Template, Template Toolkit, or something similar. But here's what you're trying to do.

#!/usr/bin/perl -w
use strict;

my $name = "Fred";

my @infile = <DATA>;
my $tmpl = join '', @infile;

# output
print eval("qq{${tmpl}}");

__DATA__
This is my template.
Here is my $name
[download]

Be warned, you can create a huge security hole by doing this.