$re = '/^\d+\.[ \t]*([^-\r\n]+?)(?:$|[ \t]*-[ \t]*(.*))/m';
$str = '4. Cost/Estimating
6. Supplier - Minor Material: Specialty
6. Supplier - Pressure Vessels & Filters
6. Supplier - Pumps
6. Supplier - Minor Material: Valves
6. Supplier - Minor Material: Specialty
6. Supplier - Other Major Equipment
7. Manufacturing
8. Project Management
9. Order Release (OTR) - Commercial Documents
9. Order Release (OTR) - Hand-Off
6. Supplier - Compressors, Drivers & Refrig. Units';
preg_match_all($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