How can I read and process (parse) command line arguments?

In Python, how can we find out the command line arguments that were provided for a script, and process them?

Related background reading: What does "sys.argv[1]" mean? (What is sys.argv, and where does it come from?). For some more specific examples, see Implementing a "[command] [action] [parameter]" style command-line interfaces? and How do I format positional argument help using Python's optparse?.

The canonical solution in the standard library is argparse (docs):

Here is an example:

from argparse import ArgumentParser

parser = ArgumentParser()
parser.add_argument("-f", "--file", dest="filename",
                    help="write report to FILE", metavar="FILE")
parser.add_argument("-q", "--quiet",
                    action="store_false", dest="verbose", default=True,
                    help="don't print status messages to stdout")

args = parser.parse_args()

argparse supports (among other things):

• Multiple options in any order.

• Short and long options.

• Default values.

• Generation of a usage help message.

Stack Overflow Q#1009860, score: 638