Run Linux command in a plugin

I was just wondering if this is possible and if it is, how would it be done?

Use shell_exec: http://php.net/manual/en/function.shell-exec.php

Thanks!

Use the backtick notation if you want to get the output directly (but thread blocking).

PHP:

$username = `whoami`;

Will both methods output the same thing?

but more convenient.

Okay