Allowing Python Script to run even on --help argument in argparse

Question

I am using Argparse module in python for developing a Command Line Tool. Here's the parser code:

from argparse import ArgumentParser

def arguments():
    parser = ArgumentParser() 
    parser.add_argument('-c' , '--comms' , action = "store" , default = None , type = str , dest = "command",
                        help = 'Choosing a Command')
    parser.add_argument( '-s' , '--search' , action = 'store' , default = None , type = str , dest = 'search_path'  ,
                        help = 'Search for a command' )
    parser.add_argument(  '-f' , '--config' , action = 'store_true' ,
                        help = 'Show the present configuration')

    parser.add_argument('--flush_details' , action = "store_false" , 
                        help = "Flushes the current commands buffer") 
    
    return parser.parse_args() 

def main():
    
    parser_results = arguments() 

    #More code comes here to analyze the results

However, when I run the code python foo.py --help, it never runs the script post parsing the arguments. Is there anything I can do to stop the behaviour. I want to analyse the parser results even if it is just asked for --help switch.

Would like to know what can I do to continue the script even after --help has been used

Using `--help` is meant to print the help **and exit**, as expected by any well-behaved command line tool. So, nothing should run afterwards, and there is nothing to analyze. What is it that you are really trying to do? — Thierry Lathuille, Dec 06 '20 at 10:46
Dumb question: why? If the user passed `-help`, what is there to parse? It is pretty universal that asking for the help prints the help message and terminates the program. Can you be more specific on your expected behavior? Are you expecting other arguments to be passed along with the `-help` argument? Please give some more run examples with their expected output. — Tomerikoo, Dec 06 '20 at 10:46
@Tomerikoo This program is actually run using a batch file. After this program exits, there is another file which will run. However, the parameters for that file is to be tweaked by this file. So if it is just --help, the next program runs using the parameters of the previous execution. Which I want to avoid. So if only --help is passed and no other parameter, the program will flush all the parameters of the next configuration to defaults. So that there is no problem or ambiguity. Which is why I don't want the program to exit — Aniruddh Anna, Dec 06 '20 at 11:00
@ThierryLathuille The script sets the parameters for the next script to run. Since it is operated in a batch execution. So if only --help is used, I want to just set the parameters to default; if the program shuts I will be left with parameters from the previous execution. Which I want to avoid. — Aniruddh Anna, Dec 06 '20 at 11:03

score 2 · Answer 1 · answered Dec 06 '20 at 11:47

Remark: you should not do that, because it does not respect established usages and may disturb users. For the remaining of the answer I shall assume that you are aware of it and have serious reasons for not respecting common usages.

The only way I can imaging is to remove the standard -h|--help processing and install your own:

parser = ArgumentParser(add_help=False) 
parser.add_argument('-h' , '--help', help = 'show this help', action='store_true')
...

Then in option processing, you just add:

parser_results = parser.parse_args()
if parser_results.help:
    parser.print_help()

user0 · Answer 2 · 2020-12-06T11:33:53.717

1

Set the add_help parameter for argparse.ArgumentParser to False to disable -h and --help:

parser=argparse.ArgumentParser(add_help=False)

Then, add --help:

parser.add_argument('--help',action='store_true')

edited Dec 06 '20 at 11:33

answered Dec 06 '20 at 11:11

user0

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The question asks how to run the script when invoking with --help and not to disable help. – Leonardus Chen Dec 06 '20 at 11:30

Leonardus Chen · Accepted Answer · 2020-12-06T11:28:49.820

As user Thierry Lathuille has said in the comments, --help is meant to print the help and exit.

If for some reason you want to print the help and run the script, you can add your own argument like so:

import argparse

parser = argparse.ArgumentParser(description="This script prints Hello World!")
parser.add_argument("-rh", "--runhelp", action="store_true", help="Print help and run function")

if __name__ == "__main__":
    args = parser.parse_args()
    if args.runhelp:
        parser.print_help()

    print('Hello World!')

If the name of the script is main.py:

>>> python main.py -rh
usage: main.py [-h] [-rh]

This script prints Hello World!

optional arguments:
  -h, --help      show this help message and exit
  -rh, --runhelp  Print help and run function
Hello World!

EDIT: If you insist on using --help instead of a custom argument:

import argparse

parser = argparse.ArgumentParser(description="This script prints Hello World!", add_help=False)
parser.add_argument("-h", "--help", action="store_true", help="Print help and run function")

if __name__ == "__main__":
    args = parser.parse_args()
    if args.help:
        parser.print_help()

    print('Hello World!')

If the name of the script is main.py:

>>> python main.py -h
usage: main.py [-h]

This script prints Hello World!

optional arguments:
  -h, --help  Print help and run function
Hello World!

Allowing Python Script to run even on --help argument in argparse

3 Answers3