I am new to PHP and I am currently studying the superglobals. I kind of understand $_SEVER and I can see how it might be used however there is not much information on $_ENV. I can't really understand the differences between the two. Here is the information from the manual and it makes no sense to me:
These variables are imported into PHP's global namespace from the environment under which the PHP parser is running. Many are provided by the shell under which PHP is running and different systems are likely running different kinds of shells, a definitive list is impossible. Please see your shell's documentation for a list of defined environment variables.
Can someone please tell me what the $_ENV, what it's used for and a practical example of the differences? I would be very grateful. I have been at this now for a while and I'm getting nowhere.