Looking at txt files within a folder...

file1.txt
file2.txt

 

<?php

    $handle = opendir('./sub');

    while(false !== ($file = readdir($handle))){

            if($file != '.' && $file != '..' && strtolower(pathinfo($file,PATHINFO_EXTENSION))=='txt') {

                       echo "$file<br />";

          }

    }
    closedir($handle);
?>