examples/argparse/argparse_positional_many.py
from __future__ import print_function
import argparse

parser = argparse.ArgumentParser()
parser.add_argument('files', help='filename(s)', nargs='+')
args = parser.parse_args()

print(args.files)

$ python argparse_positional_many.py 
usage: argparse_positional_many.py [-h] files [files ...]
argparse_positional_many.py: error: too few arguments
air:python gabor$ python argparse_positional_many.py a.txt b.txt
['a.txt', 'b.txt']