Here's another trick I've used occasionally that involves chomp.

The following code will leave a blank line at the end of <pre> blocks when the HTML is rendered:

$ perl -e '
    my $insert = <<EOF;
line1
    line2
line3
EOF
    print "<pre>$insert</pre>";
'
<pre>line1
    line2
line3
</pre>
[download]

chomp to the rescue:

$ perl -e '
    chomp(my $insert = <<EOF);
line1
    line2
line3
EOF
    print "<pre>$insert</pre>";
'
<pre>line1
    line2
line3</pre>
[download]

It can fix lots of annoying problems like that; not just <pre> blocks.