使用正则表达式从 ifconfig output 中提取 IPv4 地址

Question

嘿，我需要一点帮助来尝试使用 python 中的“重新”导入来获取网关 IP。 （我正在尝试在 eth0 中获取“广播”位）任何人都可以帮助我处理正则表达式。 非常感谢。

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
    inet 10.0.2.15  netmask 255.255.255.0  broadcast 10.0.2.255
    inet6 fe80::a00:27ff:feb4:9403  prefixlen 64  scopeid 0x20<link>
    ether 08:00:27:b4:94:03  txqueuelen 1000  (Ethernet)
    RX packets 81508  bytes 94760761 (90.3 MiB)
    RX errors 0  dropped 0  overruns 0  frame 0
    TX packets 80331  bytes 134321242 (128.0 MiB)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Answer 1

不知道为什么要对 ifconfig 的 shell output 使用正则表达式，这很容易受到 *nix、bsd 等分布之间的变化的影响。

这是一个纯 python 解决方案：

>>> import netifaces as ni
>>> ni.ifaddresses('en0')[2][0]['broadcast']
u'192.168.0.255'

Answer 2

好吧，这是两种方式。 任你选。

import re

s = """
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
    inet 10.0.2.15  netmask 255.255.255.0  broadcast 10.0.2.255
    inet6 fe80::a00:27ff:feb4:9403  prefixlen 64  scopeid 0x20<link>
    ether 08:00:27:b4:94:03  txqueuelen 1000  (Ethernet)
    RX packets 81508  bytes 94760761 (90.3 MiB)
    RX errors 0  dropped 0  overruns 0  frame 0
    TX packets 80331  bytes 134321242 (128.0 MiB)
    TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
"""

# Bit values - see /usr/include/linux/if.h
IFF_UP        = 1<<0
IFF_BROADCAST = 1<<1
IFF_RUNNING   = 1<<6
IFF_MULTICAST = 1<<12

# Method 1 - Collect the flags integer value.
rf = re.compile(r'flags=(?P<flags>\d+)')
m = rf.search(s)
if m:
    flags = int(m.group('flags'))
    print('Your flags {0:d} (decimal) is {0:X}'.format(flags, flags))

    # Note the bitwise and operator here:
    if flags & IFF_BROADCAST:
        print('BROADCAST bit is ON')

# Method 2 - Collect the flag names.
rn = re.compile(r'flags=\d+<(?P<names>.+)>')
m = rn.search(s)
if m:
    names = m.group('names').split(',')
    print('Your names are ', names)
    if 'BROADCAST' in names:
        print('BROADCAST bit is ON')