Can't get shell_exec to download a file

I have a multithreaded cli downloader for ubuntu called Aria2c.

I've been trying to get a php script to run aria2c and download a file using shell_exec, but i can't seem to get it to work. Ultimately I plan to have an input box on a page where I can ent开发者_Python百科er a link and aria would download it.

Here's the code I've come up with (for now im inputting the link manually):

<?php $dl = shell_exec('aria2c -d /home/user/ www.downloadlink.com'); ?>

Note that the aria2c command I specified works well in the shell; and the directory I'm attempting to download to is set to '777'.

I'm baffled as to why it's not working, any ideas?

PS: I prefer to use aria rather than the alternatives because it is multithreaded and it supports cookies.

Check if PHP is running in safe_mode. shell_exec won't work if safe_mode is on.

EDIT: aria2c was not referenced with a full path. Referencing it like this: shell_exec('/path/to/aria2c -d /home/user/ www.downloadlink.com') works.

I'll make the assumption that you are running PHP through a web server. In such case, it's very unlikely that the web server has permission to write into your user's home directory: Apache runs as daemon with the credentials of a limited user. Also, the PATH env variable in Apache is not necessarily the same as your user's PATH. Last but not least, you don't check the return value or the script output.

Try something like this:

<?php

exec('/path/to/aria2c -d /tmp www.downloadlink.com', $output, $return_var);

var_dump($output, $return_var);

?>

You can get the full path for aria2c with:

which aria2c