def source_interface
      # Sample output
      # ip tacacs source-interface Ethernet1/1
      # no tacacs source-interface
      match = config_get('tacacs_server', 'source_interface')
      return TacacsServer.default_source_interface if match.empty?
      # match_data will contain one of the following
      # [nil, " Ethernet1/1"] or ["no", nil]
      match[0] == 'no' ? TacacsServer.default_source_interface : match[1]
    end
def source_interface
      # Sample output
      # ip tacacs source-interface Ethernet1/1
      # no tacacs source-interface
      match = config_get('tacacs_server', 'source_interface')
      return TacacsServer.default_source_interface if match.empty?
      # match_data will contain one of the following
      # [nil, " Ethernet1/1"] or ["no", nil]
      match[0] == 'no' ? TacacsServer.default_source_interface : match[1]
    end
Get source interface