Many complex suites of applications follow a design pattern similar to the one used by the Git program. There's a base command, git, with a number of subcommands. For example, git pull, git commit, and git push.
What's central to this design is the idea of a collection of individual commands. Each of the various features of git can be thought of as a separate class definition that performs a given function.
When we enter a command such as git pull, it's as if the program, git, is locating a class to implement the command.
How can we create families of closely related commands?
