dbms_scheduler job appears to run but does not actually do anything

The environment is Oracle 11.2.0.4 on a 1/4 Exadata.  I have created a dbms_scheduler backup job that seems to execute okay, but it doesn't actually do anything.  No error is generated.  There is no output log generated either.  Please let me know what I am doing incorrectly.

Following is the script I used to create and run the job.

BEGIN

   dbms_scheduler.set_scheduler_attribute ('email_server', 'smtp.mycompany.com:25');

   dbms_scheduler.set_scheduler_attribute ('email_sender', 'do_not_reply@mycompany.com');

   dbms_scheduler.create_job (

      job_name => 'RMAN_DAILY_FRA_BACKUP',

      job_type => 'EXECUTABLE',

      job_action => '/bin/bash',