After you have created your own application (let's call it YOURAPP) you can configure FBCMD to act as YOURAPP.
You will need your Application ID (API Key) and your Application Secret Key.
You can use the SAVEPREF command to change your prefs.php file to make FBCMD always use your keys:
fbcmd SAVEPREF -appkey=YOUR_API_KEY -appsecret=YOUR_SECRET_KEY
Note: If you still want to use FBCMD regularly you will want to write a script program to call FBCMD with those arguments instead of modifying your prefs.php file. You will probably want to use a separate auth file (-auth) as well.
Just like with FBCMD, you will have to authorize YOURAPP to have access your account.
to get your 6-digit AUTH code. Once you have your code (XXXXXX) execute:
(assuming you've done the SAVEPREF command above) and you should be all set.
Also like FBCMD, you will have to grant YOURAPP permissions:
Have fun playing with your own application!