As usual, a function is not worth much until you call it. Here we check whether the program has been imported (i.e., called as part of another program) or whether it has been called independently. To do this, we check the value of __name__.
if __name__ == '__main__':
parser = OptionParser()
parser.add_option("-a", "--address", dest="address", default="localhost", help="ADDRESS for server", metavar="ADDRESS")
parser.add_option("-p", "--port", dest="port", help="PORT for server", metavar="PORT")
(options, args) = parser.parse_args()
if options.port == 'all':
print 'checking all ports...'
for x in range(1,65536):
print 'checking port %s on %s' %(x, options.address)
check = scan_server(options.address, x)
print 'scan_server returned %s' %(check)
else:
options.port = int(options.port)
print 'options: %s, args: %s' %(options, args)
check = scan_server(options.address, options.port)
print 'scan_server returned %s' %(check)
sys.exit(not check) We then call scan_server to scan the given port. Depending on whether the port instance is 'all' or not, the scan_server function will be called repeatedly with a range of addresses or once. All output goes to the screen, so be prepared for off-the-screen output if you use the 'all' option. If the value for port does not otherwise resolve to an integer through the int() function, Python will throw a ValueError. When all calls are completed, we exit the program using sys.exit().