$re = '/[1-9][2-9][0-9]\d{3,}|[1-9]\d{6,}/';
$str = '111
55
954
955
1000
0004
12000
120
999999
100000
120000
1200000
1000000
123456
222222
Log text: ajdlksjfds 120000 alskjdflskdf
Log text2: ajsldkfjsd 12000 alskdjflskdj
Log text 3: alskdjflskdjf 1000000 aslkdjflskdjf
';
preg_match_all($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