You can use backticks to quote the terminating string; you can also stack multiple heredocs. Here's an example to get the output you show:

#!/usr/bin/env perl

use strict;
use warnings;

my $rule_base = 'ip rule add fwmark 0x0201/0xffff table';
my $route_base = 'ip route add default via 172.27.201.1 dev eth1.201 t
+able';
my @table_nums = (200, 201);

my $routing_commands = <<`RULE` . <<`ROUTE`;
for i in @table_nums; do echo "$rule_base \$i"; done
RULE
for i in @table_nums; do echo "$route_base \$i"; done
ROUTE

print $routing_commands;
[download]

Output:

ip rule add fwmark 0x0201/0xffff table 200
ip rule add fwmark 0x0201/0xffff table 201
ip route add default via 172.27.201.1 dev eth1.201 table 200
ip route add default via 172.27.201.1 dev eth1.201 table 201
[download]

See "perlop: here-document syntax" for details.