$re = '/(?m)^.*?((?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s\d{2}\s\d{2}:\d{2}:\d{2}\s\d{4})/m';
$str = 'Mon Feb 19 22:25:19 2018 ABC.ls:9999: some text here, Mon Feb 19 22:25:19 2017
Mon Feb 19 22:25:20 2018 ABC.ls:9999: some text here
Mon Feb 19 22:25:20 2018 ABC.ls:9999: some text here, () with some more text';
preg_match_all($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