What are an Environment Variables in PHP?

[N I C K]

Hi friends,
I have recently started with the PHP programming language. I don't have much idea about PHP. So thought that you guys would help me in solving my doubt. I want to know what are an Environment Variables in PHP.?? Any other information about this topic would be grateful. Please help me as soon as possible.!!

[MELTRONICS]

A variable is a holder for a type of data. You can use a variable for holding numbers, strings, booleans, objects, etc. You can also keep the variable as null. You should be knowing that all the variables begin with a dollar sign "$" and the value can be assignes using the "=" operator in PHP. An environment variables in PHP are treated as regular variables. This includes the environment variables that are set by the server for a CGI program. Many useful environment variables specific to each user account are provided by the Media Temple (mt) platforms. These are available to the PHP scripting language, and their use can greatly increase the portability and maintainability of your scripts.

[Solitario]

A large number of predefined variables to all scripts are provided by the PHP. The things like built-in environment variables, last error messages to last retrieved headers are represented by the variables from an external; variables.For accessing an environment variables from php, there are two ways :

1. By using the function getenv() which will work from the CLI as well as via http.
2. You can use the global array HTTP_ENV_VARS where all environment variables are exported, if you're using PHP via HTTP. But for doing this you need to declare this as a global identifier.

[Deabelos]

You can treat environment variables in PHP as regular variables. Lets have a look on example so that you may understand more clearly. If the url of your current page is "http://www.PHPDemo.com/home/index.php", which contains the following code :

<?php
echo $_SERVER['REQUEST_URI'];
?>

Then it will print out :
/home/index.php

[kyosang]

An environment variables in PHP that are system defined variables can be accessible from anywhere inside the PHP code. The following are some of the environment variables include :

• $_SERVER - This variable contains information about the server and the HTTP connection.
• $_GET - This variable contains any information sent to the server as a search string as part of the URL.
• $_POST - This variable contains any information sent to the server as a POST style posting from a client form.
• $_COOKIE - This variable contains any cookie data sent back to the server from the client.

[Allan.d]

You can use the following code for using the environment variables :

<?php
$newVar = $_COOKIE["myCookie"];

$newVar = $HTTP_COOKIE_VARS["myCookie"];
?>