how to determine network device names

[Ralf Mardorf]

Hi,

Little Girl's second option doesn't work for me. Maybe because I'm
running Ubuntu in "container".

[root at archlinux rocketmouse]# systemd-nspawn -bqD /mnt/moonstudio
[snip]
[weremouse at moonstudio ~]$ lsb_release -a
LSB Version:	core-9.20160110ubuntu0.2-amd64:core-9.20160110ubuntu0.2-noarch:security-9.20160110ubuntu0.2-amd64:security-9.20160110ubuntu0.2-noarch
Distributor ID:	Ubuntu
Description:	Ubuntu 16.04.7 LTS
Release:	16.04
Codename:	xenial

On Sun, 7 Nov 2021 12:28:20 -0500, Little Girl wrote:
>ip address | grep "BROADCAST" | cut -d' ' -f2 | cut -d':' -f1

[weremouse at moonstudio ~]$ ip address | grep "BROADCAST" | cut -d' ' -f2 | cut -d':' -f1
enp3s0

>ip route | grep kernel | cut -f2 -d'/' | cut -f3 -d' '

[weremouse at moonstudio ~]$ ip route | grep kernel | cut -f2 -d'/' | cut -f3 -d' '
[weremouse at moonstudio ~]$ ip route
default via 192.168.1.1 dev enp3s0  proto dhcp  src 192.168.1.4  metric 1002 
192.168.1.0/24 dev enp3s0  proto dhcp  scope link  src 192.168.1.4  metric 1002 

Little Girl's second option fixed to work for me:

$ ip route | grep default | awk '{printf $5 "\n"}'
enp3s0

Another option, I'm usually using:

[weremouse at moonstudio ~]$ basename $(ls -d /sys/class/net/enp?s0)
enp3s0

In a script e.g. like this:

dhcpcd $(basename $(ls -d /sys/class/net/enp?s0))

Something to keep in mind when using the output for scripts is, that
it's possible to have more than just one "enp*" device.

Regards,
Ralf