CODEWITHSUNDEEP
linuxbash
densha
densha

Reputation: 175

Get List of Ethernet Device Names in Bash Script

I am attempting to create a bash script that creates an array of the Ethernet device names on my PC and not wireless card. I want to have a list of the names so I can later iterate over them.

For example - Assume I have two ethernet NICs - enp2s0 and enp3s0 and a wireless card - wlp4s0

From lscpi I would see

02:00.0 Ethernet controller: <truncated>
03:00.0 Ethernet controller: <truncated>
04:00.0 Network controller: Intel Corporation Wireless

Similarly ip a shows

1: lo: <truncated>
2: enp2s0: <truncated>
3: enp3s0: <truncated>
4: wlp4s0: <truncated>

How can I create an array of the names so I can iterate over them?
enp2s0 enp3s0

I have figured out how to find the first NIC using

NIC=$(basename $(udevadm info -e | grep "DEVPATH=.*$(lspci | grep -m 1  Ethernet | cut -f 1 -d\ )/net" | cut -f 2 -d\ ))

But I cannot figure out how to loop this approach. Any suggestions how I can do this in bash?

Thanks

Densha

Upvotes: 2

Views: 3302

Answers (3)

Socowi
Socowi

Reputation: 27205

nmcli has an output which can be be parsed easily, but you may have to install it first.

Example output of nmcli device:

DEVICE  TYPE      STATE        CONNECTION       
eno1    ethernet  connected    wired connection 
wlp2s0  wifi      unavailable  --               
lo      loopback  unmanaged    --

To extract only the names of ethernet devices use

nmcli device | awk '$2=="ethernet" {print $1}'

In this example the output will be eno1. You can use the command in a loop as usual.
Here we assume the first column to be free of special symbols like *[]? so that we can use the simple and portable (but potentially unsafe) construct for variable in $(command),

for device in $(nmcli device | awk '$2=="ethernet" {print $1}'); do
    # stuff
done

Upvotes: 4

densha
densha

Reputation: 175

Thanks with the suggestions I modified my original to 

for DEV in $(lspci | grep   Ethernet | cut -f 1 -d\ )
do
  NIC=$(basename $(udevadm info -e | grep "DEVPATH=.*$DEV/net" | cut -f 2 -d\ ))
  echo $NIC
done

Thanks for the suggestions

Upvotes: 0

nullPointer
nullPointer

Reputation: 4574

for f in $(ip a | grep enp | awk '{print $2}' | cut -d":" -f1)
do 
  <something with $f>
done

For devices that don't start with "enp" the below is an alternative :

for f in $(ip a | grep -B1 "ether" | grep -v ether | awk '{print $2}' | cut -d":" -f1)
do 
  <something with $f>
done

Upvotes: 0

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