getenv
Returns the value of an environment variable.
Syntax
getenv(?string $name = null, bool $local_only = false): string|array|falseParameters
| Parameter | Type | Description |
|---|---|---|
| $name | ?string | Optional. The variable name; without it all are returned. |
| $local_only | bool | Optional. Only variables set with `putenv()`. |
Return value
string|array|falseThe value, or `false` if the variable does not exist.
Examples
A default value:
<?php
putenv('APP_MODE=test');
echo getenv('APP_MODE'), "\n";
echo getenv('NO_SUCH_VARIABLE') ?: 'default';Output:
test
defaultNotes
Passwords and keys are kept in environment variables rather than in code. A missing variable gives false, not null, so ?? does not help here — use ?:.
See also
- parse_ini_file — Reads a settings file in ini format.
- define — Creates a constant at run time.
- ini_set — Changes a PHP setting for the duration of the program.
Related recipes
In the tutorial
- Configuration and environment — Where to keep the settings of a PHP project — a configuration file, environment variables, the .env file, different modes for development and the server.