$re = '/([0-9]+\s+ok\s+[0-9]+\s+nok).*?(ltelidt|eiflmrj5)/';
$str = '605sd25 schklog_1FS 13 ok 1 nok 106m 24_R23F eiflmrj5 d1us41 fd1d tm1500 o1t2enb1010 2m 2016-02-18 23:30:34 2016-02-19 07:14:01
';
$subst = "";
$result = preg_replace($re, $subst, $str, 1);
echo "The result of the substitution is ".$result;
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