network setup script

setup-network

#!/usr/bin/env python
# coding:utf8
import os
import sys

FILE_HOSTNAME = '/etc/hostname'
FILE_HOSTS = '/etc/hosts'
FILE_NETWORK = '/etc/network/interfaces'

CMD_RESTART_NETWORK = 'ifdown eth0&&ifup eth0'
CMD_UPDATE_HOSTNAME = 'hostname %s'

def readfile(filename):
    f = open(filename, 'r')
    data = f.read()
    f.close()
    return data

def writefile(filename, data):
    f = open(filename, 'w')
    f.write(data)
    f.close()

def readvalue(data, key):
    for line in data.splitlines():
        if line.startswith(key):
            val = line[len(key):]
            return val.strip()

def writevalue(data, key, value):
    lines = data.splitlines()
    for i in range(len(lines)):
        if lines[i].startswith(key):
            lines[i] = '%s\t%s' % (key, value)
    return '\n'.join(lines)

def main():
    hostname_data = readfile(FILE_HOSTNAME)
    hosts_data = readfile(FILE_HOSTS)
    network_data = readfile(FILE_NETWORK)

    hostname = hostname_data.strip()
    ip_address = readvalue(network_data, 'address')

    sys.stdout.write('Input new hostname[%s]:' % hostname)
    hostname_new = sys.stdin.readline().strip() or hostname
    
    sys.stdout.write('Input new IP address[%s]:' % ip_address)
    ip_address_new = sys.stdin.readline().strip() or ip_address

    # confirm
    sys.stdout.write('New hostname: %s\nNew IP address: %s\nOk? [Y/n]:' % (hostname_new, ip_address_new))
    confirm = sys.stdin.readline().strip()
    if confirm != 'Y':
        return

    sys.stdout.write('updating hostname...\n')
    hostname_data_new = '%s' % hostname_new
    writefile(FILE_HOSTNAME, hostname_data_new)

    sys.stdout.write('updating hosts...\n')
    hosts_data_new = writevalue(hosts_data, '127.0.1.1', hostname_new)
    writefile(FILE_HOSTS, hosts_data_new)
    os.system(CMD_UPDATE_HOSTNAME % hostname_new)

    sys.stdout.write('updating network interface...\n')
    network_data_new = writevalue(network_data, 'address', ip_address_new)
    writefile(FILE_NETWORK, network_data_new)

    sys.stdout.write('restart networking...\n')
    os.system(CMD_RESTART_NETWORK)

if __name__ == '__main__':
    main()