命令行外壳，用于识别没有IP地址的接口

Question

I am trying to filter interfaces within my machine which does not have an ip address assigned. My ifconfig output is as follows

eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.200.8.99  netmask 255.255.255.0  broadcast 10.200.8.255
        inet6 fe80::ec4:7aff:fe32:92fa  prefixlen 64  scopeid 0x20<link>
        ether 0c:c4:7a:32:92:fa  txqueuelen 1000  (Ethernet)
        RX packets 447580  bytes 44008067 (41.9 MiB)
        RX errors 0  dropped 39  overruns 0  frame 0
        TX packets 556935  bytes 91902405 (87.6 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device memory 0xfb820000-fb840000

enp2s0f2: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        ether 0c:c4:7a:15:0b:7a  txqueuelen 1000  (Ethernet)
        RX packets 16  bytes 5472 (5.3 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device memory 0xfb200000-fb300000

enp2s0f3: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        ether 0c:c4:7a:15:0b:7b  txqueuelen 1000  (Ethernet)
        RX packets 15  bytes 5130 (5.0 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device memory 0xfb100000-fb200000


virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 52:54:00:54:3b:79  txqueuelen 0  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 4  bytes 324 (324.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

I am looking for a command line shell which gives me the interfaces without IP address assigned (ie enp2s0f3, enp2s0f2).

Answer 1

$ awk -v RS= -F: '!/inet/{print $1}' file
enp2s0f2
enp2s0f3

Answer 2

A trivial state keeping mechanism allows you to keep track on where you are while reading the input line by line.

with open("/tmp/ifs") as i:
    in_if = False
    for line in i.readlines():
        if not line.startswith(" "):
            interface = line.split(":")[0]
            in_if = True
        elif in_if and line.find("inet") > 0:
            in_if = False
        elif in_if and line.find("inet") < 0:
            print(interface)
            in_if = False

Output:

enp2s0f2
enp2s0f3