cacheclean test is not robust.
sed -n '/plain success/timeout/,/Unassociated entries/p' ns2/named_dump.db.$n.b
should be checked that it contains both the start and end lines. Similarly for ns2/named_dump.db.$n.a
sed -n '/plain success/timeout/,/Unassociated entries/p' ns2/named_dump.db.$n.b
should be checked that it contains both the start and end lines. Similarly for ns2/named_dump.db.$n.a