Python example to show usage of command line arguments, configurations, and exceptions

config.ini

[helloworld]
name = Terry

config_parser.py

#!/usr/bin/python

from ConfigParser import ConfigParser, NoOptionError
import traceback

config = ConfigParser()
config.read('config.ini')

print 'an existing item value:', '[ name =', config.get('helloworld', 'name'), ']'

try:
    print 'an non-existing item value:', '[ non-exist =', config.get('helloworld', 'non-exist'), ']'
except NoOptionError:
    # pass
    traceback.print_exc()

main.py

#!/usr/bin/python

import sys, getopt

def print_usage():
    print 'main.py -i <input_file> -o <output_file>'

def main(argv):
    inputfile = ''
    outputfile = ''
    try:
        # opts is a list of returning key-value pairs, args is the options left after striped
        # the short options 'hi:o:', if an option requires an input, it should be followed by a ":"
        # the long options 'ifile=' is an option that requires an input, followed by a "="
        opts, args = getopt.getopt(argv, 'hi:o:', ['ifile=', 'ofile='])
    except getopt.GetoptError:
        print_usage()
        sys.exit(2)
    # print(args) # debug line
    if not opts:
        print_usage()
        sys.exit(2)

    # print arguments
    for opt, arg in opts:
        if opt == '-h':
            print_usage()
            sys.exit(2)
        elif opt in ("-i", "--ifile"):
            inputfile = arg
        elif opt in ("-o", "--ofile"):
            outputfile = arg
    print "Input file:", inputfile
    print "Output file:", outputfile


if __name__ == "__main__":
    main(sys.argv[1:])