A Bash script that enables/disables network adapters depending on connectivity

net-adapt.sh

#! /bin/bash

# net-adapt v0.9 (build 110915)
#
# Enables and disables WIFI device depending on ethernet connectivity
# by Sophie Forceno
#
# Distributed under an "I-don't-care-what-you-do-with-this" license

while true 
do
eth0_status=$(cat /sys/class/net/eth0/operstate)
wlan0_status=$(cat /sys/class/net/wlan0/operstate)

# Disable wifi when cable is plugged in
if [[ "$eth0_status" = "up" ]]; then 
		nmcli nm wifi off
# Enable wifi when ethernet cable is unplugged
elif [[ "$eth0_status" = "down" ]] && [[ "$wlan0_status" = "down" ]]; then
		nmcli nm wifi on
fi
sleep 2s
done