Code:
$
$ cat data.txt
AA bb, T.ST, 1013, 3, 1, 2, Jul 08 2009 10:13AM
CC, .BB, 1007, 281, 1, 1, Jul 08 2009 10:07AM
CC, .BAC, 1007, 281, 1, 1, Jul 08 2009 10:07AM
CC.DD, .BAC, 1007, 281, 1, 1, Jul 08 2009 10:07AM
CC.DD, X.BAC, 1007, 281, 1, 1, Jul 08 2009 10:07AM
CC.DD, XYBAC, 1007, 281, 1, 1, Jul 08 2009 10:07AM
CCDD, XYBAC, .1007, 281, 1, 1, Jul 08 2009 10:07AM
$
$ grep "^[^,]*, \." data.txt
CC, .BB, 1007, 281, 1, 1, Jul 08 2009 10:07AM
CC, .BAC, 1007, 281, 1, 1, Jul 08 2009 10:07AM
CC.DD, .BAC, 1007, 281, 1, 1, Jul 08 2009 10:07AM
$
$
$ perl -ne 'split; print if $_[1] =~ /^\./' data.txt
CC, .BB, 1007, 281, 1, 1, Jul 08 2009 10:07AM
CC, .BAC, 1007, 281, 1, 1, Jul 08 2009 10:07AM
CC.DD, .BAC, 1007, 281, 1, 1, Jul 08 2009 10:07AM
$