Php system() / exec() don't return output
For common commands like 'ls', exec() works fine, eg:

    exec('ls',$output,$retval);
    var_dump($output,$retval);
    // $output contains an array of filenames, and retval === 0


But when trying to execute another program, I can't get the output:

    exec('some_command --a_parameter',$output,$retval);
    var_dump($output,$retval);
    // $output contains an empty array, end $retval === 0

This command prints some lines when executing it directly from the command-line though.
I know the command has been successful because of the results (some files updated, data added, etc), and yet I can't see the output.

Any ideas?
Php system() / exec() don't return output
===

For common commands like 'ls', exec() works fine, eg:

    exec('ls',$output,$retval);
    var_dump($output,$retval);
    // $output contains an array of filenames, and retval === 0


But when trying to execute another program, I can't get the output:

    exec('some_command --a_parameter',$output,$retval);
    var_dump($output,$retval);
    // $output contains an empty array, end $retval === 0

This command prints some lines when executing it directly from the command-line though.
I know the command has been successful because of the results (some files updated, data added, etc), and yet I can't see the output.

Any ideas?