$re = '/(set [a-zA-Z0-9]+=.* &&)+ (call set [a-zA-Z0-9]+=%[a-zA-Z0-9%]+%).* call %.*%/m';
$str = 'set env1=ec && set env2=ho && call set env3=%env1% %env2% && call %env3%';
preg_match_all($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