nmcli exits with status 0 if it succeeds, a value greater than 0 is returned if an error occurs.

       0  Success – indicates the operation succeeded.

       1  Unknown or unspecified error.

       2  Invalid user input, wrong nmcli invocation.

       3  Timeout expired (see --wait option).

       4  Connection activation failed.

       5  Connection deactivation failed.

       6  Disconnecting device failed.

       7  Connection deletion failed.

       8  NetworkManager is not running.

       10 Connection, device, or access point does not exist.

       65 When used with --complete-args option, a file name is expected to follow
