Command Line call from PHP not executed

Question

I'd like to start a python application from a php script which runs on a webserver. So far, so good. I tried

passthru("python track.py"); 

but it didn't work. Simply nothing happend. I tried exec() and system() as well just to make sure. Then I tried to run a php script with:

passthru("php test.php");
passthru("/usr/bin/php test.php")

Still nothing happening. But a

passthru("ls")

just works fine as expected.

I set the permissions that every user can edit and run the files.

Answer 1

This sounds like a situation where the webserver user cannot read the file in question.

Unfortunately, passthru() simply returns NULL if a command fails, instead of throwing an exception. For example, even such nonsense as var_dump(passthru('foobar')); returns NULL .

How can you solve this? You can test from the command line if the webserver would be able to execute the command (assuming www-data is your webserver user, and you have sudo privileges):

sudo su - www-data -c 'python track.py'

This way, you'll get a meaningful error message and can solve the problem.