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Filter Out Unwanted Interfaces Using Grep

Nov 2023

When using Linux with Docker/Containers there can be a lot of virtual interfaces, while this is not a problem itself, listing just the physical interfaces can be.

For example, if we do an 'ip -br -c a' we can get quite a list:

lo               UNKNOWN        127.0.0.1/8
eno1             UP             10.32.13.233/24
eno2             UP             11.0.233.2/16
eno3             UP             12.0.233.3/16
eno4             DOWN
internalk3s0     UNKNOWN        192.168.255.1/24
kube-ipvs0       DOWN           10.43.121.13/32 10.43.139.106/32 10.43.41.193/32 10.43.199.244/32 10.43.0.10/32 10.43.88.3/32 10.43.25.131/32 10.43.120.24/32 10.43.39.71/32 10.43.212.213/32 192.168.255.1/32 10.43.41.212/32 10.43.206.154/32 10.43.148.235/32 10.43.26.88/32 10.43.217.244/32 10.43.79.27/32 10.43.115.178/32 10.43.114.120/32 10.43.66.108/32 10.43.44.118/32 10.43.136.197/32 10.43.127.60/32 10.43.138.232/32 10.43.54.183/32 10.43.110.33/32 10.43.0.1/32 10.43.60.91/32 10.43.19.143/32 10.43.123.229/32 10.43.21.162/32 10.43.92.123/32 10.43.220.178/32 10.43.87.169/32 10.43.159.224/32 10.43.18.24/32 10.43.47.137/32 10.43.24.141/32 10.43.236.14/32 10.43.17.91/32 10.43.182.233/32 10.43.195.135/32 10.43.192.38/32 10.43.157.8/32 10.43.137.179/32 10.43.196.255/32 10.43.158.51/32 10.43.23.5/32
flannel.1        UNKNOWN        10.42.0.0/32
cni0             UP             10.42.0.1/24
veth3d27dfa7@if2 UP
vethb0a17eb4@if2 UP
veth619f3a08@if2 UP
veth0977d0fb@if2 UP
vethe60bc71c@if2 UP
veth8a69f3b6@if2 UP
veth1437d366@if2 UP
veth3a247e74@if2 UP
vethc8654bec@if2 UP
veth62cbba67@if2 UP
vethfd3f5763@if2 UP
vethdd5adce6@if2 UP
veth567a8f8d@if2 UP
veth0b064639@if2 UP
vethdeed99b2@if2 UP
veth04829d3b@if2 UP
veth6660a31c@if2 UP
veth2c06a596@if2 UP
veth99db8892@if2 UP
veth47ce8ea5@if2 UP
veth976d6e7f@if2 UP
vethe4ae5d10@if2 UP
veth6c7cd23e@if2 UP
veth71d280a4@if2 UP
vethd227b1f6@if2 UP
veth55a1c60b@if2 UP
vethbc6f5ccc@if2 UP
vethc25d04a7@if2 UP
veth93d06e97@if2 UP
veth2641a619@if2 UP
veth284b1fa0@if2 UP
vethe1fdb3e7@if2 UP
veth905c6a4e@if2 UP
vethd1853059@if2 UP
veth0a79a49b@if2 UP
veth48b4b040@if2 UP
veth1ac96caa@if2 UP
veth3f9ad283@if2 UP
vethef6fb521@if2 UP
vethaacee777@if2 UP
vetha6ac44b4@if2 UP
veth05123eed@if2 UP
veth91566343@if2 UP
veth0f16c600@if2 UP