Getting all lines is done this way (if you want to catch dos, mac and unix line feeds):
$lines = explode("\n", str_replace(array("\r\n", "\r"), "\n", $string));
Filtering lines with more than one character can be done with preg_grep()
:
$lines = preg_grep('/^.{2}/', $lines);
Or using regular expressions for the complete process:
preg_match_all('/^.{2}.*$/', $string, $matches);
$lines = $matches[0];
Or if you don't need an array containing all remaining lines, you can remove the unwanted strings with a single call:
$string = preg_replace('/^.?$\n/m', '', $string);