Functions Commands Commands in are similar in principle to functions. Moreover commands typically have far more possible input parameters than functions. The second one is suitable when parameters can be entered in the right order and is similar to a function call. The third alternative is the most flexible since it allows to specified which fields should be considered as input parameters.
Fields are actually keys of a command structure.
Note that it is possible to omit the fields as long as the input parameters are entered in the right order. Since .ok was typed will not ask for more inputs and will execute the command.