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8.21. Reading Environment Variables
8.21.2. Solution
Read the value from the $_ENV superglobal array:
$name = $_ENV['USER'];
8.21.3. Discussion
Environment variables are named values associated with a process. For instance, in Unix, you can check the value of $_ENV['HOME'] to find the home directory of a user:
print $_ENV['HOME']; // user's home directory /home/adam
Early versions of PHP automatically created PHP variables for all environment variables by default. As of 4.1.0, php.ini-recommended disables this because of speed considerations; however php.ini-dist continues to enable environment variable loading for backward compatibility.
The $_ENV array is created only if the value of the variables_order configuration directive contains E. If $_ENV isn't available, use getenv( ) to retrieve an environment variable:
$path = getenv('PATH');The getenv( ) function isn't available if you're running PHP as an ISAPI module.
8.21.4. See Also
Recipe 8.22 on setting environment variables; documentation on getenv( ) at http://www.php.net/getenv; information on environment variables in PHP at http://www.php.net/reserved.variables.php#reserved.variables.environment.
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| 8.20. Logging Debugging Information |  | 8.22. Setting Environment Variables |
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