$re = '/(\d+)\s+(\S+)\s+(\w+)\s+\w+\s+\d*\s+\#\s+\S+\s+(?:\d+\s+){2}((?!.*EMPTY\b).+)$/m';
$str = 'CATALYST_TH 1
BACKPLANE A
#Slot Type Serial # Rev Num Date XptA XptB Name
2 879-858-35 0x0109037 A 0 # 0131-0 23 24 PLFD CC
6 879-857-01 0x0253bb0 A 0 # 9517-0 15 16 PMM CC-01
7 000-000-00 0x0000000 P0 0 # 0000-0 13 14 EMPTY
8 000-000-00 0x0000000 P0 0 # 0000-0 11 12 EMPTY
9 000-000-00 0x0000000 P0 0 # 0000-0 9 10 EMPTY
10 000-000-00 0x0000000 P0 0 # 0000-0 7 8 EMPTY
20 000-000-00 0x0000000 P0 0 # 0000-0 37 38 EMPTY
21 000-000-00 0x0000000 P0 0 # 0000-0 39 40 EMPTY
22 000-000-00 0x0000000 P0 0 # 0000-0 41 42 EMPTY
23 000-000-00 0x01a2446 P0 0 # 0000-0 43 44 EMPTY
1 949-669-00 0x026a850 B 0 # 0809-0 3 0 HAS (Left HAS LA669-00)
13 949-668-00 0x200762d A 0 # 9530-0 0 0 CATALYST HAC
12 949-667-00 0x026a4ee D 0 # 0102-0 0 0 DIF
24 949-669-01 0x2006037 B 0 # 9717-0 4 0 HAS (Right HAS LA669-01)
END';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php