preg_match_all($string,$pattern,$matches,PREG_PATTERN_ORDER)
$matches[0] is an array of full matches
$matches[1] is an array of strings matched by the first parenthesized
subpattern, and so on.
or
preg_match_all($string,$pattern,$matches,PREG_SET_ORDER)
Orders results so that $matches[0] is an array of first set of matches, $matches[1] is an array of
second set of matches, and so on.
for pattern use /patterntosearch/m when searching file with multiple lines