$re = '/^LIN[\s\S]*(?=^UNS)/m';
$str = 'UNB+UNOC:3+O0013001550GDID0000Z6H:14+80585:14+200218:1455+8\'
UNH+1+ORDERS:D:96B:UN\'
BGM+120+4016026958\'
DTM+4:20200218:102\'
NAD+BY+437750\'
NAD+SU+0000080585\'
NAD+OB+0000080585\'
NAD+DP+4000::9++Cronus Company:Cronus GmbH & Co. KG+Musterstrasse 3+Kirchdorf++12345+DE\'
CUX+2:EUR\'
TOD+6++DAP\'
LIN+00010++079790040080030:SA\'
PIA+1+079790040080030:SA\'
IMD+F++:::DIN 7979 D Stahl blank | 8x30 Zylin\'
QTY+12:10,000:PCE\'
PRI+AAA:23,56:::100:PCE\'
SCC+1\'
QTY+1:10,000\'
DTM+2:20200223:102\'
LIN+00020++079790040080040:SA\'
PIA+1+079790040080040:SA\'
IMD+F++:::DIN 7979 D Stahl blank | 8x40 Zylin\'
QTY+12:10,000:PCE\'
PRI+AAA:24,58:::100:PCE\'
SCC+1\'
QTY+1:10,000\'
DTM+2:20200223:102\'
LIN+00030++009128009060016:SA\'
PIA+1+009128009060016:SA\'
IMD+F++:::DIN 912 Stahl 8.8 blank | M6x16 Zyl\'
QTY+12:100,000:PCE\'
PRI+AAA:2,36:::100:PCE\'
SCC+1\'
QTY+1:100,000\'
DTM+2:20200223:102\'
UNS+S\'
UNT+35+1\'
UNZ+1+8\'
';
preg_match_all($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