This can be achieved by defining a parent parser containing the common option(s):
import argparse
parent_parser = argparse.ArgumentParser(description="The parent parser")
parent_parser.add_argument("-p", type=int, required=True,
help="set db parameter")
subparsers = parent_parser.add_subparsers(title="actions")
parser_create = subparsers.add_parser("create", parents=[parent_parser],
add_help=False,
description="The create parser",
help="create the orbix environment")
parser_create.add_argument("--name", help="name of the environment")
parser_update = subparsers.add_parser("update", parents=[parent_parser],
add_help=False,
description="The update parser",
help="update the orbix environment")
This produces help messages of the format:
parent_parser.print_help()
Output:
usage: main.py [-h] -p P {create,update} ...
The parent parser
optional arguments:
-h, --help show this help message and exit
-p P set db parameter
actions:
{create,update}
create create the orbix environment
update update the orbix environment
parser_create.print_help()
Output:
usage: main.py create [-h] -p P [--name NAME] {create,update} ...
The create parser
optional arguments:
-h, --help show this help message and exit
-p P set db parameter
--name NAME name of the environment
actions:
{create,update}
create create the orbix environment
update update the orbix environment
However, if you run your program, you will not encounter an error if you do not specify an action (i.e. create
or update
). If you desire this behavior, modify your code as follows.
<...>
subparsers = parent_parser.add_subparsers(title="actions")
subparsers.required = True
subparsers.dest = 'command'
<...>
This fix was brought up in this SO question which refers to an issue tracking a pull request.
update by @hpaulj
Due to changes in handling subparsers since 2011, it is a bad idea to use the main parser as a parent
. More generally, don't try to define the same argument (same dest
) in both main and sub parsers. The subparser values will overwrite anything set by the main (even the subparser default
does this). Create separate parser(s) to use as parents
. And as shown in the documentation, parents should use add_help=False
.