exec() runs via command line but not web

Question

I have a PHP script involving exec() that will run fine from the command line but not in a web context. The script is simply this:

Answer 1

Noticed you are writing to /home/jason. Note that apache will be the one running this command (i.e. www-data user if using Ubunut or Debian). Does the process have the correect rights to write to that folder?