$re = '/SomeText#(?:(.*?BACKUP) )?(?P<jobFileList>(?(1)[^ ]*|.*$))/m';
$str = 'SomeText#"C:\\\\","Shadow Copy Components:\\\\","E:\\\\",""
SomeText#"D:\\\\"
SomeText#"E:\\\\","Shadow Copy Components:\\\\"
SomeText#"SET SNAP_ID=serv.a.x.com_1380312019","BACKUP H:\\\\ USING \\\\\\\\?\\\\GLOBALROOT\\\\Device\\\\HarddiskVolumeShadowCopy47\\\\OPTIONS:ALT_PATH_PREFIX=c:\\\\VERITAS\\\\NetBackup\\\\temp\\\\_vrts_frzn_img_3200\\"
SomeText#"SET SNAP_ID=serv.a.x.com_1380312019","BACKUP Y:\\\\Libs USING \\\\\\\\?\\\\GLOBALROOT\\\\Device\\\\HarddiskVolumeShadowCopy47\\\\OPTIONS:ALT_PATH_PREFIX=c:\\\\VERITAS\\\\NetBackup\\\\temp\\\\_vrts_frzn_img_3200\\"
SomeText#/ahol5d72_1_2
SomeText#/p7ol4a1p_1_2
SomeText#Gvadag04SANDsk_Daily
SomeText#/bck_reco_a9ol5765_1_2_827497669';
preg_match_all($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