#!/usr/bin/python

# edit_rcconf.py

""" Функция редактирования конфигурационного файла rc.conf,
 вызывается: rcconf_edit("параметр","значение") """
def rcconf_edit(param, setting):

    # Читаем все строки в файле
    config = open('rc.conf').readlines()

    # Вычисляем номер строки, которая начинается с gateway
    num_line = 0 #Номер строки
    for line in config:
        # Если строка N num_line начинается со слова param
        if config[num_line].startswith(param):
            break
        num_line+=1
    
    # Разбиваем строку на слова
    param_sett = config[num_line].split("=")

    # Очищаем значение параметра от пробелом и сохраняем в переменную old_setting
    old_setting = param_sett[1].strip()

    # Заменяем строку "параметр = значение" на новую
    param_sett[1] = setting + "\n"
    config[num_line] = '='.join(param_sett)

    # Записываем новый конфиг в файл
    with open('rc.conf', 'w') as config_write:
        config_write.writelines(config)

# Вызываем функцию редактрирования rc.conf    
rcconf_edit("address", "192.168.1.116")

from os import linesep, rename

fname = 'rc.conf'
new_name = '%s.new' % fname
with open(fname) as inf, open(new_name, 'w') as outf:
    for line in inf:
        for name,value in (("interface", "eth0"), ("address", "192.168.1.100"),
                       ("netmask", "255.255.255.0"), ("gateway", "192.168.1.1")):
            if line.startswith(name):
                line = "%s=%s%s" % (name, value, linesep)
                break
        outf.write(line)
rename(new_name, fname)

    d = dict([("interface", "eth0"), ("address", "192.168.1.100"), ("netmask", "255.255.255.0"), ("gateway", "192.168.1.1")])
    for line in inf:
        name = line.split('=')[0].split()
        if name in d:
            line = "%s=%s%s" % (name, d[name], linesep)
        outf.write(line)

#/usr/bin/env python
#-*-coding: utf8 -*-


class CfgParser(object):
    '''
    Dict-like unix config files parser

    cfg = CfgParser('/etc/someconfig.cfg')
    print cfg['SOMEVAL']
    cfg['NEW_STR_VAL'] = 'somestring'
    cfg['NEW_INT_VAL'] = 42

    print cfg

    fd = open('/etc/someconfig.cfg', 'w')
    fd.write(repr(cfg))
    fd.close()
    '''

    def __init__(self, config=None):
        self._data = list()

        if config is not None:
            with open(config) as fd:
                self.load_lines(fd)

    def load_lines(self, iterable):
        '''
        Parse trough iterable that contains lines
        '''
        for line in iterable:
            strp = line.strip()
            if '=' not in strp or \
               strp[0] in ('#', ';'):
                self._data.append(('_COMMENT_', strp))
            else:
                name, value = strp.split('=')
                self._data.append((name, value))

    def _find_key(self, fkey):
        '''
        Find a key inside self._data
        Returns: tuple (index, value)
                 or (None, None) if key not exists
        '''
        if fkey != '_COMMENT_':
            for idx, key_val in enumerate(self._data):
                key, val = key_val
                if key == fkey:
                    return (idx, val.strip('\'\"'))
        return (None, None)

    def __getitem__(self, key):
        _, val = self._find_key(key)
        if val is None:
            raise IndexError
        return val

    def __setitem__(self, key, value):
        idx, _ = self._find_key(key)
        val = ('"%s"' % value) if isinstance(value, basestring) else value
        if idx is None:
            self._data.append((key, val))
        else:
            self._data[idx] = (key, val)

    def __delitem__(self, key):
        idx, _ = self._find_key(key)
        if idx is None:
            raise IndexError
        del self._data[idx]

    def __repr__(self):
        return '\n'.join(["%s = %s" % (key, val) if key != '_COMMENT_' else val
                                                 for key, val in self._data])


if __name__ == '__main__':
    import sys

    CONFIG_NAME = './rc.conf'

    def main(argv=None):
        cfg = CfgParser(CONFIG_NAME)

        cfg['NEW_STRING'] = 'test'
        cfg['NEW_INT'] = 89998
        cfg['HARDWARECLOCK'] = 'remote_type'
        print cfg

        return 0

    sys.exit(main(sys.argv))