$re = '/,User:\s+\"*(?<user>.+)\"*,Source computer/';
$str = '2017-02-12 14:02:05,Virus found,Source: Scheduled Scan,Risk name: OSX.Trojan.Gen,Occurrences: 1,/Users/71071190/Downloads/archive_manager.dmg,\'\',Actual action: Deleted,Requested action: Deleted,Secondary action: Deleted,Event time: 2017-02-08 22:38:17,Inserted: 2017-02-12 20:02:05,End: 2017-02-08 22:38:17,Last update time: 2017-02-12 20:02:05,Domain: North America,Group: My Company\\North America\\Workstations\\Macs,User: "ABCD, XYZ {FGH}",Source computer: ,Source IP: ,Disposition: Good,Download site: null,Web domain: null,Downloaded by: null,Prevalence: Reputation was not used in this detection.,Confidence: Reputation was not used in this detection.,URL Tracking Status: Off,,First Seen: Reputation was not used in this detection.,Sensitivity: Low,MDS,Application hash: ,Hash type: SHA1,Company name: ,Application name: ,Application version: ,Application type: -1,File size (bytes): 0,Category set: Security risk,Category type: UNKNOWN
2017-02-12 14:02:05,Virus found,Source: Scheduled Scan,Risk name: OSX.Trojan.Gen,Occurrences: 1,/Users/71071190/Downloads/archive_manager.dmg,\'\',Actual action: Deleted,Requested action: Deleted,Secondary action: Deleted,Event time: 2017-02-08 22:38:17,Inserted: 2017-02-12 20:02:05,End: 2017-02-08 22:38:17,Last update time: 2017-02-12 20:02:05,Domain: North America,Group: My Company\\North America\\Workstations\\Macs,User: 12345678,Source computer: ,Source IP: ,Disposition: Good,Download site: null,Web domain: null,Downloaded by: null,Prevalence: Reputation was not used in this detection.,Confidence: Reputation was not used in this detection.,URL Tracking Status: Off,,First Seen: Reputation was not used in this detection.,Sensitivity: Low,MDS,Application hash: ,Hash type: SHA1,Company name: ,Application name: ,Application version: ,Application type: -1,File size (bytes): 0,Category set: Security risk,Category type: UNKNOWN';
preg_match_all($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