Using the Command-Line Interface : Error Messages
  
Error Messages
If at any time the system does not recognize the command or parameter, it displays the following message:
amnesiac (config) # logging files enable
% Unrecognized command "enable".
Type "logging files?" for help.
If a command is incomplete, the following message is displayed:
amnesiac (config) # logging
% Incomplete command.
Type "logging ?" for help.