PHP Web Fundamentals Reading Environment Variables

PHP Web Fundamentals

Reading Environment Variables

Problem

You want to get the value of an environment variable.

Solution

Use getenv():

           $path = getenv('PATH');

Discussion

Environment variables are named values associated with a process. For instance, in Unix, the value of getenv('HOME') returns the home directory of a user:

           print getenv('HOME'); // user's home directory

PHP automatically loads environment variables into $_ENV by default. However, php.ini development and php.ini-production disables this because of speed considerations.

If you frequently access many environment variables, enable the $_ENV array by adding E to the variables_order configuration directive. Then you can read values from the $_ENV superglobal array. For instance:

          $name = $_ENV['USER'];

The getenv() function isn’t available if you’re running PHP as an ISAPI module.