Argparse subparser: hide metavar in command listing

Question

I'm using the Python argparse module for command line subcommands in my program. My code basically looks like this:

import argparse

parser = argparse.ArgumentParser()
subparsers = parser.add_subparsers(title="subcommands", metavar="<command>")

subparser = subparsers.add_parser("this", help="do this")
subparser = subparsers.add_parser("that", help="do that")

parser.parse_args()

When running "python test.py --help" I would like to list the available subcommands. Currently I get this output:

usage: test.py [-h] <command> ...

optional arguments:
  -h, --help  show this help message and exit

subcommands:
  <command>
    this      do this
    that      do that

Can I somehow remove the <command> line in the subcommands listing and still keep it in the usage line? I have tried to give help=argparse.SUPPRESS as argument to add_subparsers, but that just hides all the subcommands in the help output.

Answer 1

I solved it by adding a new HelpFormatter that just removes the line if formatting a PARSER action:

class SubcommandHelpFormatter(argparse.RawDescriptionHelpFormatter):
    def _format_action(self, action):
        parts = super(argparse.RawDescriptionHelpFormatter, self)._format_action(action)
        if action.nargs == argparse.PARSER:
            parts = "\n".join(parts.split("\n")[1:])
        return parts