my @lines = &read_all_lines_into_an_array();

# Here you set the values for the variables you want
# interpolated later...

eval qq{print "$_\n"} for @lines;


##</code><code>##

for my $line (@lines) {
    for my $var ('@scalars_to_interpolate) {
	eval qq{\$line =~ s/\\$var/$var/g}, "\n";
    }
    print $line, "\n";
}