Python2 example to handle options and arguments.

getopt.py

import sys, os, getopt

TARGET_TYPE = ".log"

def process_file(path):
    ''' Process a file. '''
    print path


def process_dir(path):
    ''' Process a directory. '''
    file_list = []
    files = os.listdir(path)
    for file in files:
        file = os.path.join(path, file)
        root, ext = os.path.splitext(os.path.basename(file))
        if os.path.isfile(file) and ext == TARGET_TYPE:
            process_file(file)


def main():
    if len(sys.argv) < 2:
        print "Arguments should be at least 2."
        print "python get_blockid.py -f [FILE]"
        print "python get_blockid.py -d [DIRECTORY]"
        exit(1)

    try:
        opts, args = getopt.getopt(sys.argv[1:], "f:d:", ["file=", "directory="])
        for arg, value in opts:
            if arg in ('-f', '--file'):
                root, ext = os.path.basename(value)
                if ext == 'TARGET_TYPE':
                    process_file(value)
            elif arg in ('-d', '--directory'):
                process_dir(value)
            else:
                print "Argument error. %s" % arg
                exit(1)
    except getopt.GetoptError as e:
        print e
        exit(1)


if __name__ == '__main__':
    main()