$re = '/(?:IF|ELSE) ([A-Z]+) -> ([A-Z]+) IN\(( (?:"[A-Z0-9]{2}"(?:[, ])*)+)\)(?: +)THEN ([A-Z0-9\-]+) ="([A-Z]+)"/m';
$str = 'IF KNVV -> KDGRP IN( "EK", "ES" ) THEN KNA1-SORTL ="KA"
ELSE KNVV -> KDGRP IN( "EL", "E3", "E5", "E7", "E2", "EF" ) THEN KNA1-SORTL ="IN"
ELSE KNVV -> KDGRP IN( "EX", "EU", "EV", "ET", "EW" ) THEN KNA1-SORTL ="CA"
END';
preg_match_all($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