addsubparsers

add_subparsers is a method of the argparse module in Python, belonging to the ArgumentParser class. It creates and manages subcommands within a command-line interface by adding a SubParsersAction to the top-level parser. The method returns this action, which is then used to add individual subparsers for each subcommand.

To use subparsers, first create them on the main parser by calling add_subparsers and optionally specify a destination attribute with dest. A common pattern is to set dest to a name such as 'command', so the chosen subcommand is stored in args.command after parsing. You may also specify required to enforce that a subcommand must be provided (a feature available in recent Python versions).

For each subcommand, create a dedicated subparser with subparsers.add_parser('name', help='...'). The parser returned by add_parser is its own ArgumentParser and can define its own set of options and positional arguments. This allows each subcommand to have distinct behavior and argument sets. After parsing, the arguments belonging to the chosen subparser are included in the parsed result, while irrelevant subcommand arguments are ignored.

Common usage patterns include wiring a function to a subcommand using set_defaults(func=…) so that the chosen subcommand directly dispatches to the corresponding handler. Subparsers also support optional metadata such as title and description for better help output, and can be organized to mirror complex CLI structures like version control or package management tools.

Overall, add_subparsers enables modular command-line interfaces by cleanly separating subcommands and their arguments, while keeping the top-level parser focused on shared options.