cli/documentation/en_US/aaa/aaa-authorization-example

aaa authorization exec default group tacacs+
  Use TACACS+ for authorizing CLI access

aaa authorization exec default local
  Use local UNIX /etc/passwd for authorizing CLI access

aaa authorization exec default group tacacs+ local
  Use both TACACS+ and /etc/passwd for CLI authorization

no aaa authorization exec default
  Reset authorization sources for SSH CLI access.