I want to store tweets that I find after a search, in a text file

Does anyone know how could I save the tweets after searching in a .txt file? My index file is the following:

     <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
     <html xmlns="http://www.w3.org/1999/xhtml">
     <head>
     <title>Twitter</title>
     </head>
     <body>
  <?php
     require('twitter.class.php');
     $twitter = new twitter_class();
     echo $twitter->getTweets('tomato', 15);
   ?>
   </body>
   </html>

I'm new to all this so I would appreciate any help.

Solution

Here is the code to save the tweets:

<?php
    require('twitter.class.php');
    $twitter = new twitter_class();
    $tweets = $twitter->getTweets('tomato', 15);
    $currentfile = file_get_contents('tweets.txt');
    file_put_contents('tweets.txt', $currentfile.$tweets);
?>

This will append the tweets instead of erasing the data if you don't want to append tweets just do this:

<?php
    require('twitter.class.php');
    $twitter = new twitter_class();
    $tweets = $twitter->getTweets('tomato', 15);
    file_put_contents('tweets.txt', $tweets);
?>