allow predictable network interfaces

on dual-eth-raspi:
- eth0 -> end0
- eth1 -> enx...

to_system/etc/profile.d/welcome.sh

@@ -1,7 +1,12 @@
 export EDITOR=nano
 echo "-----------------------------------------------------"
 echo "Welcome to $HOSTNAME $(hostname -I)"
-echo "ethernet addr $(cat /sys/class/net/eth0/address)"
+if [[ -f /sys/class/net/eth0/address ]]; then
+  ETHNAME=$(cat /sys/class/net/eth0/address)
+else
+  ETHNAME=$(cat /sys/class/net/end0/address)
+fi
+echo "ethernet addr $ETHNAME"
 function service_status () {
     for name in $@; do \
       enabled=$(systemctl is-enabled ${name} 2> /dev/null) && \