f = open(lock,'w+') f.close() except: pass #even if lock file cannot be created proceed with the rest of the code log = None url = None maxlinks = None cmdlength = len(sys.argv) if cmdlength < 2 : print("Please enter url to crawl and the maximum number of links to be extracted which is an optional one") print("Eg 1: python Main.py http://python.org 50") print("Eg 2: python Main.py http://python.org") sys.exit() elif cmdlength == 2 or cmdlength == 3: url = str(sys.argv[1]) if not URLValidator.isValidURL(url): print("Either your url is not valid or a format that cannot be crawled") sys.exit() if cmdlength == 3: try: maxlinks = int(sys.argv[2]) except ValueError: print('Invalid maximum links') sys.exit() if maxlinks < 1: print("maximum links should be minimum 1") sys.exit() else: print("Invalid number of arguments") sys.exit() try: