title: How do I access and modify PHP variables in external files?
body: <p>Back again with another basic question. So I have a php file (main.php) where I am connecting to my mysql database, and am connecting to it via "include 'main.php'". I want to create some variables in this file that I can manipulate and essentially be able to work with and change their values, but be able to see their changes on any other webpage. For example, let's say I have the main.php file as mentioned above, index.php, and next.php, and main.php has a variable $test="0". I want to be able to assign $test a value in index, let's say $test=10, and be able to work with that in next.php, so if I do echo 5+$test, I want the output to be 15, not 5.</p>
  
  <p>Thank you very much!</p>