Python in a Nutshell

Interactive Command Sessions

The cmd module offers a simple way to handle interactive sessions of commands. Each command is a line of text. The first word of each command is a verb defining the requested action. The rest of the line is passed as an argument to the method that implements the action that the verb requests.

Module cmd supplies class Cmd to use as a base class, and you define your own subclass of cmd.Cmd. The subclass supplies methods with names starting with do_ and help_, and may also optionally override some of Cmd’s methods. When the user enters a command line such as verb and the rest, as long as the subclass defines a method named do_ verb, Cmd.onecmd calls:

self.do_verb('and 
               the 
               rest')

Similarly, as long as the subclass defines a method named help_ verb, Cmd.do_help calls it when the command line starts with either 'help verb' or '? verb‘. Cmd, by default, also shows suitable error messages if the user tries to use, or asks for help about, a verb for which the subclass does not define a needed method.

Methods of Cmd Instances

An instance c of a subclass of class Cmd supplies the following methods (many of these methods are meant to be overridden by the subclass).

Attributes of Cmd Instances

An instance c of a subclass of class Cmd supplies the following attributes:

identchars

A string that contains all characters that can be part of a verb; by default, c .identchars contains letters, digits, and underscore (_)

intro

The message that cmdloop outputs first, ...