$_ENV

$HTTP_ENV_VARS [已弃用]

$_ENV -- $HTTP_ENV_VARS [已弃用]环境变量

说明

通过环境方式传递给当前脚本的变量的数组

这些变量被从 PHP 解析器的运行环境导入到 PHP 的全局命名空间。很多是由支持 PHP 运行的 Shell 提供的,并且不同的系统很可能运行着不同种类的 Shell,所以不可能有一份确定的列表。请查看你的 Shell 文档来获取定义的环境变量列表。

其他环境变量包含了 CGI 变量,而不管 PHP 是以服务器模块还是 CGI 处理器的方式运行。

$HTTP_ENV_VARS 包含相同的信息,但它不是一个超全局变量。 (注意 $HTTP_ENV_VARS$_ENV 是不同的变量,PHP 处理它们的方式不同)

更新日志

版本 说明
4.1.0 引入 $_ENV,弃用 $HTTP_ENV_VARS

范例

Example #1 $_ENV 范例

<?php
echo 'My username is ' .$_ENV["USER"] . '!';
?>

假设 "bjori" 运行此段脚本

以上例程的输出类似于:

My username is bjori!

注释

Note:

"Superglobal"也称为自动化的全局变量。这就表示其在脚本的所有作用域中都是可用的。不需要在函数或方法中用 global $variable; 来访问它。

参见

User Contributed Notes

kobenews at cox dot net 17-Apr-2018 09:08
If running php-fpm with the default production variables_order = GPCS, $_ENV will always be an empty array. Instead of reading the superglobal $_ENV use the built-in function getenv() or read from $_SERVER['ENV-KEY-HERE'].
Guy 06-Mar-2018 10:06
@Tit Petric - I believe you meant: clear_env=no

not clean_env

Set the above in your PHP-FPM config to prevent clearing ENV vars
Tit Petric 28-Apr-2017 09:39
If you're using php-fpm you might want to set `clean_env = no`. This setting cleans the environment variables by default, meaning that PHP would be started with a clean environment.
aasasdasdf at yandex dot ru 08-Apr-2014 02:25
Please note that writing to $_ENV does not actually set an environment variable, i.e. the variable will not propagate to any child processes you launch (except forked script processes, in which case it's just a variable in the script's memory). To set real environment variables, you must use putenv().

Basically, setting a variable in $_ENV does not have any meaning besides setting or overriding a script-wide global variable. Thus, one should never modify $_ENV except for testing purposes (and then be careful to use putenv() too, if appropriate).

PHP  will not trigger any kind of error or notice when writing to $_ENV.
david at davidfavor dot com 07-Feb-2012 02:07
Comments for this page seem to indicate getenv() returns environment variables in all cases.

For getenv() to work, php.ini variables_order must contain 'E'.
anonymous 09-Sep-2010 10:36
If $_ENV is empty because variables_order does not include it, it will be filled with values fetched by getenv().

For example, when calling getenv("REMOTE_ADDR"), $_ENV['REMOTE_ADDR'] will be defined as well (if such an environment variable exists).
gabe-php at mudbugmedia dot com 26-May-2010 09:11
If your $_ENV array is mysteriously empty, but you still see the variables when calling getenv() or in your phpinfo(), check your http://us.php.net/manual/en/ini.core.php#ini.variables-order ini setting to ensure it includes "E" in the string.
php at isnoop dot net 01-Apr-2010 09:33
If you wish to define an environment variable in your Apache vhost file, use the directive SetEnv.

SetEnv varname "variable value"

It is important to note that this new variable will appear in $_SERVER, not $_ENV.
ewilde aht bsmdevelopment dawt com 20-Mar-2009 05:48
When running a PHP program under the command line, the $_SERVER["SERVER_NAME"] variable does not contain the hostname. However, the following works for me under Unix/Linux and Windows:

<?php
if (isset($_ENV["HOSTNAME"]))
   
$MachineName = $_ENV["HOSTNAME"];
else if  (isset(
$_ENV["COMPUTERNAME"]))
   
$MachineName = $_ENV["COMPUTERNAME"];
else
$MachineName = "";
?>