After posting the heredoc with backticks solution, I thought of another way that required no escaping.

$ cat pm_1223868_heredoc_awk_2.pl
#!/usr/bin/env perl

use strict;
use warnings;

open my $fh, '-|', q[echo "a b c" | awk '{print $2}'];
print <$fh>;
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$ pm_1223868_heredoc_awk_2.pl
b
[download]

That's just the guts of the solution. You'll need to add error handling at least. See open for more about this.