cli-args.py

#!/usr/bin/env python

from argparse import ArgumentParser, FileType

# ------------------------------------------------------------------------------
# defaults
# ------------------------------------------------------------------------------

default_nthreads = 1
default_verbose = False

# ------------------------------------------------------------------------------
# parsing arguments
# ------------------------------------------------------------------------------

parser = ArgumentParser(
    description = 'awesome python script',
    epilog      = "use with caution, the awesomeness might slap you in the face!"
)

parser.add_argument("input",  help = "path to input file",  type = FileType('r'))
parser.add_argument("output", help = "path to output file", type = FileType('w'))

parser.add_argument(
    "-t", "--threads",
    help = "number of threads to use, defaults to " + str(default_nthreads),
    dest = "nthreads",
    default = default_nthreads,
    metavar = 4
)

parser.add_argument(
    "-v", "--verbose",
    help = "print more output on what's happening",
    action = 'store_true',
    default = default_verbose
)

options = parser.parse_args()

# ------------------------------------------------------------------------------
# assign a few shortcuts
# ------------------------------------------------------------------------------

verbose      = options.verbose
input_file   = options.input
output_file  = options.output

# ------------------------------------------------------------------------------
# actual program
# ------------------------------------------------------------------------------

if verbose:
    print("[info] listing options now ...")

print("number of threads: {}".format(options.nthreads))
print("input: {}".format(input_file.name))
print("output: {}".format(output_file.name))

if verbose:
    print("[info] end of script")