$lines_array = file("file.txt");
$search_string = "bing";
foreach($lines_array as $line) {
if(strpos($line, $search_string) !== false) {
list(, $new_str) = explode(":", $line);
// If you don't want the space before the word bong, uncomment the following line.
//$new_str = trim($new_str);
}
}
echo $new_str;
?>