title: PHP deleting the second line in a file if the file is of a certain length
body: <p>When a user signs up for an account on my website their own page is created called USERNAME.php. <br/>Whenever the username "bob" gets signed in then a new line is added to bob.php which contains the time, date and ip address of that login.<br/><br/> What I want to do is have a maximum of 20 lines in that file, so that the file doesn't get too big over time. <br/>I have the first line as "Login Retrieval for <strong>bob</strong>" and then the most recent login result at the bottom. So the first line should not be deleted, but the second line should be deleted with every login (only if the amount of lines is > 20). What would be the best way to go about doing this? Thanks!</p>