When I think of fixed-length fields, I always think of unpack:

my $data = '19600326';

print join('-', unpack('A4A2A2', $data));
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or

my $data = '19600326';

printf ('%s-%s-%s', unpack('A4A2A2', $data));
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Update: Ack! Zaxo beat me to it by a couple of minutes. :-)

Impossible Robot