There is a lot going on here in this example! Let's look through the command entries as they occur in the text.
The first command, mysqluc, starts the users' console. Once the console starts, you will see a welcome banner followed by a simple prompt, mysqluc>. No additional options or parameters are necessary. However, it should be noted that you can pass commands to the console to execute on start. For a complete list of options, see MySQL Users' Console manual page.
The next command, help, shows the help for the users' console itself. As you can see, there are a number of options available. You can set user defined variables, discover the help for other utilities, display the latest error, and see the options used to start the console.
The help utilities command shows you a list of the available utilities and a short description of each.
Next, we decide we want to get help for one of the database utilities but we do not remember the name. We know it starts with mysqldb but we are not sure of the rest. In this case, if we type mysqldb then hit TAB twice, the users' console will show us a list of all of the utilities that begin with mysqldb. Very nice!
Now let's say we want to see a graph of our replication topology but we are not sure what the option for specifying the master. In this case, we type the command to launch the mysqlrplshow utility and type the start of the option, '--m', then press TAB twice. What we see is there are two options that match that prefix. Notice we also see a short description (help) for each. This is a real time saving feature for the users' console.
Notice in the next segment we do not have to type the entire name of the option. In this case we typed '--mast[TAB]' which the users' console completed with '--master='. This is tab completion for option names. Also very nice.
Notice the result of the command we entered, mysqlrplshow '--master=<user>:<password>@localhost:13001'. There was an error here. We can see the error with the show errors command. We see in the error we failed to provide any connection information for the slaves.
Once we correct that omission, the last command shows how the users' console executes a utility and displays the results in the same stream as the console - much like the mysql client tool.