How do i do this?

Hi all im currently creating a console mode php program that prompts the user for a string intil the user enters quit. Once quit has been entered it will then prompt the user if they want it converted to upper or lower case, and then redisplay it. Heres the code so far,

#!/usr/local/bin/php -q
<?php
//phpprogram.php
require ("phpio");
print("\n ");
$txt="type the word quit";
print $txt;
print ("\n\n");
$input = input();
if ($txt <=$txt)
{
  print("\n  ");
  print "do you want to convert this to upper or lower case";
}
print ("\n\n");
$input = input();
print ("\n\n");
?>

Code (markup):

I've never done upper/lower case before so i'm not sure how to even do it. Anyone know what i need to do and the code i need to add? Thanks.

 

strtolower() and strtoupper(), follow the examples their.

 

No problem Any help at all would be much appreciated.

 

Well what I posted should solve/answer your question.