Noob who wants a script to execute on hang up

General Help
1

Assume I’m a noob.

I want to call a shell script when a specific extension (21) hangs up on an outgoing call.

I’m using
Your Linux Distribution: (Redhat CentOS release 6.3 (Final))
Your FreePBX version: (2.8.1)

it looks like I can do this from /etc/asterisk/extension_custom.conf with a system call.

Permissions (for testing) of the script are 777.

but I’ve looked around and I just can’t make it work.

Keep in mind that everything I’ve done before this has been through the web gui, so I am really over my head doing this by hand.

If someone could point me in the right direction, that would be grand.

2

What type of telephones are you using?
Some have an Action URI or Action URL that could be used to call a script when the handset is hung up.