A simple downloader for .gitgnore files

getignore.py

#!/usr/bin/env python3

from urllib.request import Request, urlopen
from urllib.error import HTTPError
import sys, os
import argparse

url = "https://raw.githubusercontent.com/github/gitignore/master/{}.gitignore"


parser = argparse.ArgumentParser(description="Downloads a .gitignore file suited for a certain configuration")
parser.add_argument('--append', dest="append", action="store_true", help="Appends the content to a preexisting .gitignore. If overwrite is set, this flag is ignored")
parser.add_argument('--overwrite', dest="overwrite", action="store_true", help="Overwrites an existing .gigitnore file")
parser.add_argument('--file-name', dest="file_name", default='.gitignore', type=str, help="Uses the given filename as the name of the file instead of .gitignore")
parser.add_argument('name', type=str, help="The name of the gitignore file")
parser.add_argument('url', nargs='?', type=str, help="The url from where to fetch the gitignore files", default=url)
args = parser.parse_args()

overwrite = args.overwrite
append = args.append
file_name = args.file_name
name = args.name
url = args.url.format(args.name)


try:
    with urlopen(url, data=None, timeout=10) as r:
        if overwrite:
            mode = 'w+b'
        elif append:
            mode = 'a+b'
        else:
            if os.path.isfile(file_name):
                sys.stderr.write('File %s already exists. Use --overwrite or --append\n' % file_name)
                sys.exit(1)
            else: 
                mode = 'ab'
        try:
            with open(file_name, mode) as f:
                f.write(r.read())
        except IOError as ie:
            sys.stderr.write('%s\n' % ie)
except HTTPError as e:
	print("Error while downloading: %s" % e)