Simple PHP editor of text files

You create a HTML form to edit the text-file's content. In case it get's submitted, you update the text-file (and redirect to the form again to prevent F5/Refresh warnings):

<?php// configuration$url = 'http://example.com/backend/editor.php';$file = '/path/to/txt/file';// check if form has been submittedif (isset($_POST['text'])){    // save the text contents    file_put_contents($file, $_POST['text']);    // redirect to form again    header(sprintf('Location: %s', $url));    printf('<a href="%s">Moved</a>.', htmlspecialchars($url));    exit();}// read the textfile$text = file_get_contents($file);?><!-- HTML form --><form action="" method="post"><textarea name="text"><?php echo htmlspecialchars($text) ?></textarea><input type="submit" /><input type="reset" /></form>

To read the file:

<?php    $file = "pages/file.txt";    if(isset($_POST))    {        $postedHTML = $_POST['html']; // You want to make this more secure!        file_put_contents($file, $postedHTML);    }?><form action="" method="post">    <?php    $content = file_get_contents($file);    echo "<textarea name='html'>" . htmlspecialchars($content) . "</textarea>";    ?>    <input type="submit" value="Edit page" /></form>

You're basically looking for a similar concept to that of a contact-form or alike.

Apply the same principles from a tutorial like this one and instead of emailing using mail check out the file functions from PHP.net.