Python implementation of ssh-keyscan utility

ssh-keyscan.py

#!/usr/bin/env python3
import argparse
import paramiko
import os.path

parser = argparse.ArgumentParser()
parser.add_argument('host', action='store', help='host to connect to')
parser.add_argument('-p', '--port', action='store', dest='port', default='22', help='port to connect to')
parser.add_argument('--known_hosts', action='store', dest='known_hosts', default='~/.ssh/known_hosts', help='known_hosts file')
args = parser.parse_args()

host = args.host
address = args.host+':'+args.port

if os.path.isfile(args.known_hosts):
    known_hosts = args.known_hosts
else:
    open(args.known_hosts, 'w').close()
    known_hosts = args.known_hosts


transport = paramiko.Transport(address)

transport.connect()
key = transport.get_remote_server_key()
transport.close()


hostfile = paramiko.HostKeys(filename=known_hosts)
hostfile.add(hostname = host, key=key, keytype=key.get_name())

hostfile.save(filename=known_hosts)

@bitinerant, thank you for your reply!
All fixed up!