PostgreSQL: output from multi-line pl/pgsql from psql from perl

#!/usr/bin/perl

my $cmd = "psql -Xq --set ON_ERROR_STOP=on --dbname crmmbqt <<'EOS'
";
$cmd .= <<'END';
do
$$
begin
    raise notice '%', pg_is_in_recovery();
end
$$
END
$cmd .= 'EOS
';

print `$cmd`;