How to set command line environment variable in PHP shell_exec

Question

The script I am trying to run via shell_exec in PHP requires an environmental variable to be set, which afaik is done via:

export VARIABLE=value

However, to run the script I am forced to do:

<?PHP
$sOutput = shell_exec("export VARIABLE=value && my_command_goeth_hereth");

It seams kinda pointless to have to export the variable every time I run any commands.

Is this the only way to do it, or am I missing a much simpler way?

Solution 1

Since environment variables are inherited, setting them inside your script will set them for the commands it launches too. You just have to use putenv.

putenv("VARIABLE=value");

Solution 2

Won't just:

<?PHP
shell_exec('SOMEVAR=SOMEVAL /some/program');

do the trick?

If you're running multiple shell scripts, then putenv is your friend, as zneak pointed out.

EDIT with an exmaple:

env.php:

<?PHP
echo $_ENV['FOO'];
echo "\n";

runenv.php:

<?PHP
echo shell_exec('FOO=bar php env.php');

then try $ php runenv.php

Comments

[Stephen RC]

Why is this any different from what I am doing above? i.e. export VARIABLE=value && command

[timdev]

it's nearly the same thing. But you don't need to export if you just want the environment to apply to a single script/program. More than one and you're probably better off with putenv()