$re = '`File=[^=]+/(\w+=[^/]+)/([^_]+)[^:\s]*file\.xml(\.[^:\s]*):([^,\s]*)`m';
$str = 'Node=LTE03:File=/PMloc/dir22/XML/Network=ARX_ROOT_AO,Network=LTE,Network=Base,Manage=LTE,Element=LTE03/A20210115.1545+0530-1600+0530_Network=ARX_ROOT_AO,Network=LTE,Network=Base,Manage=LTE,Element=LTE03_file.xml.gz:Unit=U-3,Meter=1
';
preg_match_all($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