$re = '/(END).*?(START)/s';
$str = 'STARTsadasd
asdasd
asdasd
asdas
das
dasdasdasd
asdasd
sadasdENDasdasd
asdasd
asdasdasf
asdfsdfsdf
sdfsd
fsdf
sdfasdsad
sd
fsd
fsdfsdfsdf
sadadSTARTsdasfgsdhtrwe
asdasdasdasd
asdasd
asdasdasf
asdfsdfsdf
sdfsd
fsdf
sdfasdsad
sd
fsd
fsdfsdfsdf
sadadsdENDsadasd
asdasd
asdasdasf
asdfsdfsdf
sdfsd
fsdf
sdfasdsad
sd
fsd
fsdfsdfsdf
START
asdasd
asdasdasf
asdfsdfsdf
sdfsd
fsdf
sdfasdsad
sd
fsd
fsdfsdfsdf
AsdgrrgerENDetrtwtw
asdasdSTARTsadasd
asdasd
asdasd
asdas
das
dasdasdasd
asdasd
sadasdENDasdasd
asdasd
asdasdasf
asdfsdfsdf
sdfsd
fsdf
sdfasdsad
sd
fsd
fsdfsdfsdf
sadadSTARTsdasfgsdhtrwe
asdasdasdasd
asdasd
asdasdasf
asdfsdfsdf
sdfsd
fsdf
sdfasdsad
sd
fsd
fsdfsdfsdf
sadadsdENDsadasd
asdasd
asdasdasf
asdfsdfsdf
sdfsd
fsdf
sdfasdsad
sd
fsd
fsdfsdfsdf
START
asdasd
asdasdasf
asdfsdfsdf
sdfsd
fsdf
sdfasdsad
sd
fsd
fsdfsdfsdf
AsdgrrgerEND';
preg_match_all($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