The primary service. Specifying a service attribute indicates that this is a request for authorization or accounting of that service.
Current values are slip , ppp , arap , shell , tty-daemon , connection , and system .
This attribute must always be included. This indicates the command name for a shell command that is to be run. A NULL value indicates that the shell itself is being referred to. This indicates an argument for the shell command that is to be run. Multiple cmd-arg attributes may be specified, and they are order dependent.