为了配ip 只想简单点，再简单点

#!/usr/bin/env python

import sys
import re

def configip(fname, ip_addr, if_ind):
    content = """TYPE=Ethernet
BOOTPROTO=none
NAME=eth%s
DEVICE=eth%s
ONBOOT=yes
IPADDR=%s
PREFIX=24
""" % (if_ind, if_ind, ip_addr)
    with open(fname, 'w') as fobj:
        fobj.write(content)

def check_ip(ip_addr):
    m = re.match(r'(\d{1,3}\.){3}\d{1,3}$', ip_addr)
    if not m:
        return False
    return True

def show_menu():
    prompt = """Configure IP Address:
(0) eth0
(1) eth1
(2) eth2
(3) eth3
Your choice(0/1/2/3): """
    try:
        if_ind = raw_input(prompt).strip()[0]
    except:
        print 'Invalid input.'
        sys.exit(1)

    if if_ind not in '0123':
        print 'Wrong Selection. Use 0/1/2/3'
        sys.exit(2)

    fname = '/etc/sysconfig/network-scripts/ifcfg-eth%s' % if_ind
    ip_addr = raw_input('ip address: ').strip()
    result = check_ip(ip_addr)
    if not result:
        print 'Invalid ip address'
        sys.exit(3)
    configip(fname, ip_addr, if_ind)
    print '\033[32;1mConfigure ip address done. Please execute "systemctl restart NetworkManager"\033[0m'

if __name__ == '__main__':
    show_menu()