Command line utility?

Question

linux

How are commands actually implemented in command-line utilities? Those. they are not requested (if we talk about python for example) by input and a dictionary? For some reason, after all, the utility parameters pop up if you press TAB? How it's done? I wanted to write one utility and now I'm thinking how to make it more beautiful.

Answer 1

https://habrahabr.ru/post/71525/

Answer 2

Of course, it would not be good to ask for all command line arguments with input and a dictionary. There are libraries for this: here is argparse
And for TAB autocompletion too: argcomplete

Answer 3

Writing your own completions for Shell